AEGiS-13IAC: Detection and quantitation of antigen specific CD8 T lymphocytes in HIV infected children.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

Detection and quantitation of antigen specific CD8 T lymphocytes in HIV infected children.

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. MoOrA224)

Pahwa S, McCloskey TW, Haridas V, Bakshi S, Chavan S
S. Pahwa, North Shore University Hospital, 350 Community Drive, Manhasset, NY 11030, United States, Tel.: +516 562-4641, Fax: +516 562-2866, E-mail: spahwa@nshs.edu

BACKGROUND: Antigen specific CD8 T lymphocytes comprise a major component of the cellular immune response against viral pathogens and can be detected and quantified by tetramer reagents.

METHODS: Fluorescently labeled tetramers for HIV gag `HLA-A*0201/SLYNTVATL' and pol `HLA-A*0201/ILKEPVHGV' were utilized to quantify antigen specific cells in a cohort of HLA-A2+ HIV infected children `age: median 9 years, range 1 month-17 years; CD4 count: median 735 cells/ul, range 27-1503 cells/ul; virus load: median 946 RNA copies/ml, range 50-134,702 RNA copies/ml; 16/19 receiving combination antiretroviral therapy'. Blood samples were labeled with tetramer in combination with anti CD8 fluorescein and anti CD3 phycoerythrin monoclonal antibodies prior to analysis by flow cytometry.

RESULTS: Gag binding CD8 T cells were detectable in 17/19 children `median of 0.4% of total CD8 T cells', including 4/5 with under 100 RNA copies/ml of virus. Pol binding cells were observed in 14/19 subjects `median of 0.1% of total CD8 T cells'. There was a strong correlation between the number of gag and pol binding cells `r = 0.719, p = 0.003' in the 14 children in whom both were detected, also in the total number of CD8 T cells `r = 0.675, p = 0.008 for gag; r = 0.771, p = 0.0001 for pol', and a moderate correlation with the total number of CD4 T cells `r = 0.631, p = 0.01 for gag; r = 0.552; p = 0.04 for pol'. No relationship to plasma viral load was detected.

CONCLUSIONS: Antigen binding CD8 T lymphocytes were detectable in the majority of children. Correlation between the number of gag and pol binding cells suggest host and/or viral factors which influence the ability to respond to particular epitopes. Correlation with CD4 may reflect the importance of CD4 help for an adequate antigen specific CD8 response.

Keywords: AEGIS, Antigens, CD8, HIV, HIV Infections, Viral Load, CD8-Positive T-Lymphocytes, CD4-Positive T-Lymphocytes, HIV Antigens, CD4 Lymphocyte Count, HIV Seropositivity, Anti-HIV Agents, Flow Cytometry, Antigens, CD4, Child, Human, immunology
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MoOrA224