NOKTA MA, LI X, NICHOLS J, POLLARD RB; Interscience Conference on Antimicrobial Agents and Chemotherapy (41st : 2001 : Chicago, Ill.).
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2001 Dec 16-19; 41: abstract no. I-1952.
University of Texas Medical Branch, Galveston, TX
BACKGROUND: Recall antigen memory responses are impaired in HIV-infected patients. These responses are dependent on the balance between CD95 and CD28 costimulatory signal expression. In this report the CD95 and CD28 expression on CD4 and CD8 cells were examined and their relationship to recall antigen responses and cell associated HIV RNA determined. METHODS: Twenty-six HIV[+] subjects and 12 HIV seronegative control subjects participated in this study. The CD4 counts of those patients ranged from 25 to 1156 (median, 422 cells/mm[3]) and plasma HIV RNA ranged from undetectable to 7.5 x 10[5] (median 1200 copies/ml). Co-expression of CD95 and CD28 were measured by flow cytometry, recall antigen helper function by determining CMV-induced lymphoproliferative responses, cellular and plasma viral load by quantitative RT-PCR. RESULTS: CD28 expression on CD4 (87 +/- 3) and CD8 (37 +/- 4) T cells in HIV[+] patients were decreased as compared to the controls 100% and 66 +/- 4% respectively. Most of the decreases were in the CD28[+]CD95[-] subset rather than the CD28[+]CD95[+] subset. The CD28[+]CD95[-], CD4 subset positively correlated with the stimulation index (SI) for CMV Ag (r = 0.8, p< 0.0001). Interestingly the CD28[+]CD95[+] subset inversely correlated with the CMV-induced response (r = -0.73, p < 0.005). The CMV SI correlated with % CD4 (r = 0.6, p < 0.05) and was inversely related to cell associated HIV RNA (r = -0.67 p < 0.05). Enrichment of CD95[-]CD28[+]CD4[+] T cells by depletion of CD95[+]CD4[+] cells enhanced the SI for CMV Ag by 3 fold in HIV seronegative controls. CONCLUSIONS: CD28 expression on CD4 and CD8 T cells is down regulated in HIV-infected subjects. The recall Ag CMV specific response is strongly associated with CD28 expression on the CD4 T cell subset that is CD95[-]. Moreover CD95 expression on CD28[+] CD4[+] T cells appears to inhibit CD4 mediated T cell helper function.
Publication Types:
Keywords:
- AIDS Vaccines
- Acquired Immunodeficiency Syndrome
- Antigens, CD28
- Antigens, CD4
- Antigens, CD8
- Antigens, CD95
- CD4-Positive T-Lymphocytes
- CD8-Positive T-Lymphocytes
- HIV Infections
- HIV Seropositivity
- Humans
- Immunologic Memory
- T-Lymphocytes
- Viral Load
- immunology
Other ID:
UI: 102269341
From Meeting Abstracts