Ronnarit Haponsaph. The effect of CD8+ T lymphocytes on the replication of HIV-1 subtypes B and E in Thai donor cells . Doctoral Degree(Immunology). Mahidol University. : Mahidol University, 2003.
The effect of CD8+ T lymphocytes on the replication of HIV-1 subtypes B and E in Thai donor cells
Abstract:
Differences in HLA type and in the immunophenotype of lymphocyte subsetshave been reported for Thais versus North Americans. These factors may play a rolein the replication and pathogenesis of HIV in different ethnic groups. The objectivesof this study were to determine the growth kinetics of HIV subtype B and CRF01_AE(E) in peripheral blood mononuclear cells (PBMC) from HIV seronegative Thaidonors, to determine the relationship between MHC serotype and growth kinetics ofHIV subtype B and E isolates in Thai donors, and to investigate whether Thai donorCD8+ cells can be infected with HIV-1 in vitro.
Donor PBMC were prepared from whole blood samples of Thai subjects usingficoll-hypaque gradient centrifugation; cells were also cryopreserved for use inmultiple experiments. Cells were thawed and immunophenotyped for CD3, CD4 andCD8 using a Becton Dickinson FACSort flow cytometer. T and B cells were isolatedfrom PBMC for HLA class I and II typing, respectively.The CD4+ cells weredepleted from a portion of the PBMC by immunomagnetic bead selection (Dynal,Inc.). PBMC or CD8-enriched PBMC were stimulated with phytohemagglutinin(PHA) for 24 hrs and cultured with interleukin-2 (IL-2). After 4 days, cells wereimmunophenotyped again and infected with varying doses of virus. At days 4, 7 and10 supernatant was harvested for extracellular p24 quantitation by antigen captureELISA, and cells were harvested for intracellular p24 determination by flowcytometry.
As previously reported for North American donors, variation in the susceptibilityto HIV-1 infection was observed amongst Thai donors. For example, donorNORM025 was highly susceptible to HIV-1 infection, while donor NORM027showed minimal infection. The level of infection was, in part, related to the % CD8+cells in the PBMC, as donor NORM027 had 70% CD8s, while donor NORM025 had35% CD8s. However MHC phenotypes for slow and rapid progression seemed to beunrelated to donor susceptibility to HIV-1 infection in vitro. In donor NORM025,1%-2% of the CD8+ cells were p24+, and only a subset of these infected cells wereCD4+/CD8+. In conclusion, our findings showed that CD8-enriched PBMC could beinfected with HIV-1 and that CD8+ T cells, as well as other factors, may influenceHIV replication in cells from Thai donors.