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Fulltext A tryptophan metabolite made by a gut microbiome eukaryote induces pro-inflammatory T cells

Wojciech L, Png CW, Koh EY, Kioh DYQ, Deng L, Wang Z, et al.

EMBO J, 2023 Nov 02;42(21):e112963.
PMID: 37743772 DOI: 10.15252/embj.2022112963

The large intestine harbors microorganisms playing unique roles in host physiology. The beneficial or detrimental outcome of host-microbiome coexistence depends largely on the balance between regulators and responder intestinal CD4+ T cells. We found that ulcerative colitis-like changes in the large intestine after infection with the protist Blastocystis ST7 in a mouse model are associated with reduction of anti-inflammatory Treg cells and simultaneous expansion of pro-inflammatory Th17 responders. These alterations in CD4+ T cells depended on the tryptophan metabolite indole-3-acetaldehyde (I3AA) produced by this single-cell eukaryote. I3AA reduced the Treg subset in vivo and iTreg development in vitro by modifying their sensing of TGFβ, concomitantly affecting recognition of self-flora antigens by conventional CD4+ T cells. Parasite-derived I3AA also induces over-exuberant TCR signaling, manifested by increased CD69 expression and downregulation of co-inhibitor PD-1. We have thus identified a new mechanism dictating CD4+ fate decisions. The findings thus shine a new light on the ability of the protist microbiome and tryptophan metabolites, derived from them or other sources, to modulate the adaptive immune compartment, particularly in the context of gut inflammatory disorders.

Matched MeSH terms: T-Lymphocytes, Regulatory
Regulation of CD8+ T-cell cytotoxicity in HIV-1 infection

Saeidi A, Buggert M, Che KF, Kong YY, Velu V, Larsson M, et al.

Cell Immunol, 2015 Nov-Dec;298(1-2):126-33.
PMID: 26520669 DOI: 10.1016/j.cellimm.2015.10.009

Understanding the mechanisms involved in cellular immune responses against control of human immunodeficiency virus (HIV) infection is key to development of effective immunotherapeutic strategies against viral proliferation. Clear insights into the regulation of cytotoxic CD8+ T cells is crucial to development of effective immunotherapeutic strategies due to their unique ability to eliminate virus-infected cells during the course of infection. Here, we reviewed the roles of transcription factors, co-inhibitory molecules and regulatory cytokines following HIV infection and their potential significance in regulating the cytotoxic potentials of CD8+ T cells.

Matched MeSH terms: T-Lymphocytes, Cytotoxic/immunology*
Fulltext Biomarkers of severe dengue disease - a review

John DV, Lin YS, Perng GC

J Biomed Sci, 2015;22:83.
PMID: 26462910 DOI: 10.1186/s12929-015-0191-6

Dengue virus infection presents a wide spectrum of manifestations including asymptomatic condition, dengue fever (DF), or severe forms, such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) in affected individuals. The early prediction of severe dengue in patients without any warning signs who may later develop severe DHF is very important to choose appropriate intensive supportive therapy since available vaccines for immunization are yet to be approved. Severe dengue responses include T and B cell activation and apoptosis, cytokine storm, hematologic disorders and complement activation. Cytokines, complement and other unidentified factors may transiently act on the endothelium and alter normal fluid barrier function of the endothelial cells and cause plasma leakage. In this review, the host factors such as activated immune and endothelial cells and their products which can be utilized as biomarkers for severe dengue disease are discussed.

Matched MeSH terms: T-Lymphocytes/metabolism*
Increased regulatory T cells in acute lymphoblastic leukaemia patients

Idris SZ, Hassan N, Lee LJ, Md Noor S, Osman R, Abdul-Jalil M, et al.

Hematology, 2016 May;21(4):206-12.
PMID: 26907959 DOI: 10.1080/10245332.2015.1101965

INTRODUCTION: Regulation in adaptive immune response balances a fine line that prevents instigation of self-damage or fall into unresponsiveness permitting abnormal cell growth. Mechanisms that keep this balance in check include regulatory T cells (Tregs). Tregs consist of a small but heterogeneous population, which may be identified by the phenotype, CD3+CD4+CD25+CD127-. The role of Tregs in pathogenesis of cancers is thus far supported by evidence of increased Tregs in various cancers and may contribute to poorer prognosis. Tregs may also be important in acute leukaemias.
OBJECTIVE: A review of the literature on Tregs in acute leukaemias was conducted and Tregs were determined in B-cell acute lymphoblastic leukaemias (ALLs).
RESULTS: Studies on Tregs in B-cell ALL are few and controversial. We observed a significantly increased percentage of Tregs (mean±SD, 9.72 ± 3.79% vs. 7.05 ± 1.74%; P = 0.047) in the bone marrow/peripheral blood of ALL (n = 17) compared to peripheral blood of normal controls (n = 35). A positive trend between Tregs and age (R = 0.474, P = 0.055, n = 17) implicates this factor of poor prognosis in B-cell ALL.
DISCUSSION: Tregs in cancer are particularly significant in immunotherapy. The manipulation of the immune system to treat cancer has for a long time ignored regulatory mechanisms inducible or in place. In lymphoma studies, tumour-specific mechanisms that are unlike conventional methods in the induction of Tregs have been hypothesized. In addition, tumour-infiltrating Tregs may present different profiles from peripheral blood pictures. Tregs will continue to be dissected to reveal its mysteries and their impact on clinical significance.

Matched MeSH terms: T-Lymphocytes, Regulatory/immunology*
Immunomodulation in Middle-Aged Humans Via the Ingestion of Physta® Standardized Root Water Extract of Eurycoma longifolia Jack--A Randomized, Double-Blind, Placebo-Controlled, Parallel Study

George A, Suzuki N, Abas AB, Mohri K, Utsuyama M, Hirokawa K, et al.

Phytother Res, 2016 Apr;30(4):627-35.
PMID: 26816234 DOI: 10.1002/ptr.5571

This study was aimed to investigate the capacity of a standardized root water extract of Eurycoma longifolia (Tongkat Ali, TA), Physta® to modulate human immunity in a middle-aged Japanese population. This randomized, double-blind, placebo-controlled, parallel study was conducted for 4 weeks. Eighty-four of 126 subjects had relatively lower scores according to Scoring of Immunological Vigor (SIV) screening. Subjects were instructed to ingest either 200 mg/day of TA or rice powder as a placebo for 4 weeks [TA and Placebo (P) groups] and to visit a clinic in Tokyo twice (weeks 0 and 4). SIV, immunological grade, immunological age, and other immune parameters were measured. Eighty-three subjects completed the study; 40 in the TA group and 41 in the P group were statistically analyzed, whereas two were excluded from the analyses. At week 4, the SIV and immunological grade were significantly higher in the TA group than those in P group (p T cells were also higher in the TA group than those in P group (p

Matched MeSH terms: T-Lymphocytes/drug effects
Comparison of three forms of antigens in the demonstration of cell-mediated immune response in murine toxoplasmosis

Rahmah N, Khairul Anuar A

Biochem Biophys Res Commun, 1992 Dec 15;189(2):640-4.
PMID: 1472034

Mice were chronically infected with cysts of ME49 strain of Toxoplasma gondii. At different periods post-infection, their spleens were removed and single cell suspensions were made. Lymphocyte transformation experiments were performed on the lymphocyte suspensions using three different kinds of antigens of ME49 strain of T. gondii, namely soluble, excretory/secretory and cystic forms. The results showed that the pattern of lymphocyte responsiveness was dependent on the kind of antigen employed for induction of the blastogenesis. Using soluble and cystic forms of the antigen, different periods of lymphocyte suppression and lymphocyte proliferation were demonstrated. However, with the use of excretory/secretory antigen, no significant suppression of lymphocyte stimulation was noted throughout the course of infection. Thus excretory/secretory antigen may be the best form of antigen for stimulation of the cell-mediated immune response and hence it appears to be a good candidate for vaccine in toxoplasmosis.

Matched MeSH terms: T-Lymphocytes/immunology*
The distribution of immunoregulatory cells in the peripheral blood of normal Malaysian adults

Chin SF, Cheong SK, Lim YC, Ton SH

Malays J Pathol, 1993 Jun;15(1):49-52.
PMID: 8277790

The distribution of immunoregulatory cells in the peripheral blood of an individual has now been established as an important tool in helping the management of several diseases. It is necessary to set the normal ranges of these cells for the laboratory. We have undertaken in this study to establish the reference ranges for normal Malaysian adults. We found that the mean percentages of T cells, B cells, T Helper cells (CD4), T suppressor cells (CD8), NK cells and the ratio of CD4/CD8 were 70.91%, 11.38%, 38.15%, 37.76%, 17.45%, and 1.00 respectively. There was no significant difference between the sexes. In certain parameters, there was significant differences between Malay, Chinese and Indians. The Chinese and Indians were significantly different in the distribution of B cells and in the CD4/CD8 ratio. In the case of CD4 and NK cells, the Indians were different from the other two groups.

Matched MeSH terms: T-Lymphocytes*
T cell-mediated cytotoxicity against dengue-infected target cells

Pang T, Devi S, Blanden RV, Lam SK

Microbiol. Immunol., 1988;32(5):511-8.
PMID: 3262810 DOI: 10.1111/j.1348-0421.1988.tb01411.x

A cytotoxic T lymphocyte (CTL) response to dengue virus-infected target cells is described. Effector cells were generated in an in vitro secondary culture and appeared to be T cells possessing both the Lyt 1.1 and Lyt 2.1 surface antigens. A stronger CTL response was noted with the H-2k haplotype compared to H-2d, and H-2 compatibility was required between CTL and target cells. CTL generated showed some cross-reactivity with target cells infected with Japanese encephalitis virus (JEV), another flavivirus, but not with target cells infected with an alphavirus, Sindbis. The significance and importance of these findings are discussed.

Matched MeSH terms: T-Lymphocytes, Cytotoxic/immunology*
Fulltext Aberrancies of human T--and B--lymphocyte populations in peripheral blood

Gan SC, Yeoh CW

Med J Malaysia, 1980 Jun;34(4):379-82.
PMID: 6971393

Strict precautions were taken in our methodology to exclude any monocytes from being included in the total T and B cell estimation. There is a progressive drop in the percentage of T and B cells with age, but no significant differences between the races nor between the sexes of the same age group. Aberrancies of T and B cell percentages were noted in most infections, malignancies and even malnutrition.

Matched MeSH terms: T-Lymphocytes*
Mycobacterium leprae reactive T cell clones from lepromatous leprosy patients after prolonged dapsone chemotherapy

Gill HK, Ridley DS, Ganesan J, Mustafa AS, Rees RJ, Godal T

Lepr Rev, 1990 Mar;61(1):25-31.
PMID: 2181222

The proliferative responses of peripheral blood mononuclear cells (PBMC) to Mycobacterium leprae and BCG were studied in two groups of leprosy patients: a group of 8 lepromatous patients who had been on treatment for more than 20 years (TLL) and a group of 8 untreated lepromatous leprosy patients (ULL). The mean response to M. leprae of the TLL group was 6195 cpm with 5 of the 8 patients responding positively. The mean response to M. leprae of the ULL group was 617 cpm, with only 1 patient showing a positive response. The corresponding proliferative responses to BCG were 19,908 cpm in the TLL group and 7908 in the ULL group. Thirteen M. leprae reactive clones were established from 2 TLL patients and 5 M. leprae reactive clones were established from 2 tuberculoid leprosy patients. Seven of these clones, 4 from the TLL patients and 3 from the tuberculoid (TT) patients could be studied further. Three of the TLL clones responded specifically to M. leprae, while one of the clones exhibited a broad cross-reactivity to other mycobacteria. All of these clones were of the CD4+CD8- phenotype. Our findings suggest that responsiveness to M. leprae can be detected in vitro in a proportion of LL patients who have undergone prolonged chemotherapy, and that this response involves M. leprae reactive CD8+CD8- T cells, of which some appear to be specific to M. leprae.

Matched MeSH terms: T-Lymphocytes/immunology*
Overview of Current Immunotherapies Targeting Mutated KRAS Cancers

Hoo WPY, Siak PY, In LLA

Curr Top Med Chem, 2019;19(23):2158-2175.
PMID: 31483231 DOI: 10.2174/1568026619666190904163524

The occurrence of somatic substitution mutations of the KRAS proto-oncogene is highly prevalent in certain cancer types, which often leads to constant activation of proliferative pathways and subsequent neoplastic transformation. It is often seen as a gateway mutation in carcinogenesis and has been commonly deemed as a predictive biomarker for poor prognosis and relapse when conventional chemotherapeutics are employed. Additionally, its mutational status also renders EGFR targeted therapies ineffective owing to its downstream location. Efforts to discover new approaches targeting this menacing culprit have been ongoing for years without much success, and with incidences of KRAS positive cancer patients being on the rise, researchers are now turning towards immunotherapies as the way forward. In this scoping review, recent immunotherapeutic developments and advances in both preclinical and clinical studies targeting K-ras directly or indirectly via its downstream signal transduction machinery will be discussed. Additionally, some of the challenges and limitations of various K-ras targeting immunotherapeutic approaches such as vaccines, adoptive T cell therapies, and checkpoint inhibitors against KRAS positive cancers will be deliberated.

Matched MeSH terms: T-Lymphocytes/immunology*
Fulltext Hypomethylating Agents and Immunotherapy: Therapeutic Synergism in Acute Myeloid Leukemia and Myelodysplastic Syndromes

Wong KK, Hassan R, Yaacob NS

Front Oncol, 2021;11:624742.
PMID: 33718188 DOI: 10.3389/fonc.2021.624742

Decitabine and guadecitabine are hypomethylating agents (HMAs) that exert inhibitory effects against cancer cells. This includes stimulation of anti-tumor immunity in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) patients. Treatment of AML and MDS patients with the HMAs confers upregulation of cancer/testis antigens (CTAs) expression including the highly immunogenic CTA NY-ESO-1. This leads to activation of CD4+ and CD8+ T cells for elimination of cancer cells, and it establishes the feasibility to combine cancer vaccine with HMAs to enhance vaccine immunogenicity. Moreover, decitabine and guadecitabine induce the expression of immune checkpoint molecules in AML cells. In this review, the accumulating knowledge on the immunopotentiating properties of decitabine and guadecitabine in AML and MDS patients are presented and discussed. In summary, combination of decitabine or guadecitabine with NY-ESO-1 vaccine enhances vaccine immunogenicity in AML patients. T cells from AML patients stimulated with dendritic cell (DC)/AML fusion vaccine and guadecitabine display increased capacity to lyse AML cells. Moreover, decitabine enhances NK cell-mediated cytotoxicity or CD123-specific chimeric antigen receptor-engineered T cells antileukemic activities against AML. Furthermore, combination of either HMAs with immune checkpoint blockade (ICB) therapy may circumvent their resistance. Finally, clinical trials of either HMAs combined with cancer vaccines, NK cell infusion or ICB therapy in relapsed/refractory AML and high-risk MDS patients are currently underway, highlighting the promising efficacy of HMAs and immunotherapy synergy against these malignancies.

Matched MeSH terms: CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes
Fulltext TREM-1 activation is a potential key regulator in driving severe pathogenesis of enterovirus A71 infection

Amrun SN, Tan JJL, Rickett NY, Cox JA, Lee B, Griffiths MJ, et al.

Sci Rep, 2020 03 02;10(1):3810.
PMID: 32123257 DOI: 10.1038/s41598-020-60761-5

Hand, foot and mouth disease (HFMD), caused by enterovirus A71 (EV-A71), presents mild to severe disease, and sometimes fatal neurological and respiratory manifestations. However, reasons for the severe pathogenesis remain undefined. To investigate this, infection and viral kinetics of EV-A71 isolates from clinical disease (mild, moderate and severe) from Sarawak, Malaysia, were characterised in human rhabdomyosarcoma (RD), neuroblastoma (SH-SY5Y) and peripheral blood mononuclear cells (PBMCs). High resolution transcriptomics was used to decipher EV-A71-host interactions in PBMCs. Ingenuity analyses revealed similar pathways triggered by all EV-A71 isolates, although the extent of activation varied. Importantly, several pathways were found to be specific to the severe isolate, including triggering receptor expressed on myeloid cells 1 (TREM-1) signalling. Depletion of TREM-1 in EV-A71-infected PBMCs with peptide LP17 resulted in decreased levels of pro-inflammatory genes for the moderate and severe isolates. Mechanistically, this is the first report describing the transcriptome profiles during EV-A71 infections in primary human cells, and the potential involvement of TREM-1 in the severe disease pathogenesis, thus providing new insights for future treatment targets.

Matched MeSH terms: T-Lymphocytes/virology
Fulltext Targeting dendritic cells through gold nanoparticles: A review on the cellular uptake and subsequent immunological properties

Ahmad S, Zamry AA, Tan HT, Wong KK, Lim J, Mohamud R

Mol Immunol, 2017 11;91:123-133.
PMID: 28898717 DOI: 10.1016/j.molimm.2017.09.001

Gold nanoparticles (NPs) have been proposed as a highly potential tool in immunotherapies due to its advantageous properties including customizable size and shapes, surface functionality and biocompatibility. Dendritic cells (DCs), the sentinels of immune response, have been of interest to be manipulated by using gold NPs for targeted delivery of immunotherapeutic agent. Researches done especially in human DCs showed a variation of gold NPs effects on cellular uptake and internalization, DC maturation and subsequent T cells priming as well as cytotoxicity. In this review, we describe the synthesis and physiochemical properties of gold NPs as well as the importance of gold NPs in immunotherapies through their actions on human DCs.

Matched MeSH terms: T-Lymphocytes/immunology
An immune-inspired swarm aggregation algorithm for self-healing swarm robotic systems

Timmis J, Ismail AR, Bjerknes JD, Winfield AF

Biosystems, 2016 Aug;146:60-76.
PMID: 27178784 DOI: 10.1016/j.biosystems.2016.04.001

Swarm robotics is concerned with the decentralised coordination of multiple robots having only limited communication and interaction abilities. Although fault tolerance and robustness to individual robot failures have often been used to justify the use of swarm robotic systems, recent studies have shown that swarm robotic systems are susceptible to certain types of failure. In this paper we propose an approach to self-healing swarm robotic systems and take inspiration from the process of granuloma formation, a process of containment and repair found in the immune system. We use a case study of a swarm performing team work where previous works have demonstrated that partially failed robots have the most detrimental effect on overall swarm behaviour. We have developed an immune inspired approach that permits the recovery from certain failure modes during operation of the swarm, overcoming issues that effect swarm behaviour associated with partially failed robots.

Matched MeSH terms: T-Lymphocytes/immunology
Fulltext Negligible effect of chicken cytokine IL-12 integration into recombinant fowlpox viruses expressing avian influenza virus neuraminidase N1 on host cellular immune responses

Majid NN, Omar AR, Mariatulqabtiah AR

J Gen Virol, 2020 07;101(7):772-777.
PMID: 32427095 DOI: 10.1099/jgv.0.001428

In comparison to the extensive characterization of haemagglutinin antibodies of avian influenza virus (AIV), the role of neuraminidase (NA) as an immunogen is less well understood. This study describes the construction and cellular responses of recombinant fowlpox viruses (rFWPV) strain FP9, co-expressing NA N1 gene of AIV A/Chicken/Malaysia/5858/2004, and chicken IL-12 gene. Our data shows that the N1 and IL-12 proteins were successfully expressed from the recombinants with 48 kD and 70 kD molecular weights, respectively. Upon inoculation into specific-pathogen-free (SPF) chickens at 105 p.f.u. ml-1, levels of CD3+/CD4+ and CD3+/CD8+ populations were higher in the wild-type fowlpox virus FP9 strain, compared to those of rFWPV-N1 and rFWPV-N1-IL-12 at weeks 2 and 5 time points. Furthermore, rFWPV-N1-IL-12 showed a suppressive effect on chicken body weight within 4 weeks after inoculation. We suggest that co-expression of N1 with or without IL-12 offers undesirable quality as a potential AIV vaccine candidate.

Matched MeSH terms: CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes
Coinfection between SARS-CoV-2 and HIV with a low CD4+ T-cells count

Suryana K CS

Med J Malaysia, 2021 05;76(3):446-448.
PMID: 34031352

Coronavirus Disease 2019 (COVID-19) is an acute respiratory infectious disease caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection that started in Wuhan, China in December 2019 and has spread rapidly worldwide. It's critical to take extra precautions if a person has chronic illnesses (comorbidities), such as human immunodeficiency (HIV) infection. Concerns about people living with HIV (PLHIV) having a higher risk of serious COVID-19 disease may be based on the assumption that PLHIV are more likely to be immunocompromised. On the other hand, limited information is available in such people about the characteristics of co-infection between SARS-CoV-2 and Human Immunodeficiency Virus (HIV) who are at greater risk than the general population. Our findings, is of a 32 year old patient who came to Emergency Unit of Wangaya Hospital, Medical Faculty, Udayana University in Denpasar, Bali with complaint of fever, dry cough, and shortness of breath since prior 3 days and had also the past history prolonged fever, weight loss more than 10% 4 weeks. Diagnosis of COVID-19 was confirmed by nasopharyngeal swab sample was used for RT-PCR assay and PITC to confirm HIV infection. He had prolonged hospitalized and discharge after 18 days.

Matched MeSH terms: CD4-Positive T-Lymphocytes/metabolism*
Fulltext Function of PD-L1 in antitumor immunity of glioma cells

Lou Y, Shi J, Guo D, Qureshi AK, Song L

Saudi J Biol Sci, 2017 May;24(4):803-807.
PMID: 28490949 DOI: 10.1016/j.sjbs.2015.06.025

Human glioma is a highly fatal tumor with a significant feature of immune suppression. The functions of PD-L1 refer to co-simulation and immune regulation. To investigate expression and functional activity of PD-L1 in human glioma cell in vivo and in vitro. Expressions of PD-L1mRNA and protein in the human glioma cell line were analyzed with quantitative RT-PCR and flow cytometer; and then expression of PD-L1 in tissue specimens of 10 glioma patients was treated with immunohistochemical analysis; glioma cell and allogeneic CD4+ and CD8+ T cells were co-cultured, and cytokine IFN-γ, IL-2 and IL-10 in cultured supernatant fluid were determined with ELISA; upon blocking the interaction between glioma cell and the immune cell with PD-L1 monoclonal antibody (5H1), surface markers on immune cells were analyzed using flow cytometer. All human glioma cell lines constitutively expressed PD-L1, and IFN-γ induced glioma cell to highly express PD-L1. It was shown through immunohistochemical analysis that glioma specimen expressed PD-L1, while expression of PD-L1 was not observed in normal tissue and normal human brain near the tumor location. The release of IFN-γ and IL-2 was inhibited, while IL-10 was increased slightly. Glioma cell may escape from immune recognition and injury with the help of PD-L1, which is a significant pathogenic mechanism of glioma.

Matched MeSH terms: CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes
Fulltext Molecular Signatures of Human Regulatory T Cells in Colorectal Cancer and Polyps

Johdi NA, Ait-Tahar K, Sagap I, Jamal R

Front Immunol, 2017;8:620.
PMID: 28611777 DOI: 10.3389/fimmu.2017.00620

Regulatory T cells (Tregs), a subset of CD4(+) or CD8(+) T cells, play a pivotal role in regulating immune homeostasis. An increase in Tregs was reported in many tumors to be associated with immune suppression and evasion in cancer patients. Despite the importance of Tregs, the molecular signatures that contributed to their pathophysiological relevance remain poorly understood and controversial. In this study, we explored the gene expression profiles in Tregs derived from patients with colorectal cancer [colorectal carcinoma (CRC), n = 15], colorectal polyps (P, n = 15), and in healthy volunteers (N, n = 15). Tregs were analyzed using CD4(+)CD25(+)CD127(low)FoxP3(+) antibody markers. Gene expression profiling analysis leads to the identification of 61 and 66 immune-related genes in Tregs derived from CRC and P patients, respectively, but not in N-derived Treg samples. Of these, 30 genes were differentially expressed both in CRC- and P-derived Tregs when compared to N-derived Tregs. Most of the identified genes were involved in cytokine/chemokine mediators of inflammation, chemokine receptor, lymphocyte activation, and T cell receptor (TCR) signaling pathways. This study highlights some of the molecular signatures that may affect Tregs' expansion and possible suppression of function in cancer development. Our findings may provide a better understanding of the immunomodulatory nature of Tregs and could, therefore, open up new avenues in immunotherapy.

Matched MeSH terms: CD8-Positive T-Lymphocytes; T-Lymphocytes, Regulatory
Fulltext Characterization of antiviral T cell responses during primary and secondary challenge of laboratory cats with feline infectious peritonitis virus (FIPV)

Mustaffa-Kamal F, Liu H, Pedersen NC, Sparger EE

BMC Vet Res, 2019 May 22;15(1):165.
PMID: 31118053 DOI: 10.1186/s12917-019-1909-6

BACKGROUND: Feline infectious peritonitis (FIP) is considered highly fatal in its naturally occurring form, although up to 36% of cats resist disease after experimental infection, suggesting that cats in nature may also resist development of FIP in the face of infection with FIP virus (FIPV). Previous experimental FIPV infection studies suggested a role for cell-mediated immunity in resistance to development of FIP. This experimental FIPV infection study in specific pathogen free (SPF) kittens describes longitudinal antiviral T cell responses and clinical outcomes ranging from rapid progression, slow progression, and resistance to disease.
RESULTS: Differences in disease outcome provided an opportunity to investigate the role of T cell immunity to FIP determined by T cell subset proliferation after stimulation with different viral antigens. Reduced total white blood cell (WBC), lymphocyte and T cell counts in blood were observed during primary acute infection for all experimental groups including cats that survived without clinical FIP. Antiviral T cell responses during early primary infection were also similar between cats that developed FIP and cats remaining healthy. Recovery of antiviral T cell responses during the later phase of acute infection was observed in a subset of cats that survived longer or resisted disease compared to cats showing rapid disease progression. More robust T cell responses at terminal time points were observed in lymph nodes compared to blood in cats that developed FIP. Cats that survived primary infection were challenged a second time to pathogenic FIPV and tested for antiviral T cell responses over a four week period. Nine of ten rechallenged cats did not develop FIP or T cell depletion and all cats demonstrated antiviral T cell responses at multiple time points after rechallenge.
CONCLUSIONS: In summary, definitive adaptive T cell responses predictive of disease outcome were not detected during the early phase of primary FIPV infection. However emergence of antiviral T cell responses after a second exposure to FIPV, implicated cellular immunity in the control of FIPV infection and disease progression. Virus host interactions during very early stages of FIPV infection warrant further investigation to elucidate host resistance to FIP.

Matched MeSH terms: T-Lymphocytes/immunology*

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