AEGiS-15IAC: Breadth and persistence of cross-reactive T-cell responses in HIV CRF01_AE or B-infected injection drug users (IDUs).

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Breadth and persistence of cross-reactive T-cell responses in HIV CRF01_AE or B-infected injection drug users (IDUs).

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. A10150)

McNicholl JM, Thielen C, Promadej-Lanier N, Chaowanachan T, Vanichseni S, Choopanya K, Young N, Martin M, Mastro TD, Tappero J, Hu DJ
Centers for Disease Control and Prevention, Atlanta, United States

BACKGROUND: Cross-reactive T cell responses may provide protection from HIV infection or superinfection and are thus important to consider for HIV vaccine design. Two HIV-1 subtypes, CRF01_AE (E) and B, accounted for all incident infections, including two cases of inter-subtype superinfection, in a prospective cohort study of IDUs in Bangkok, Thailand. We have characterized cross-reactive T-cell responses in this cohort.

METHODS: Peripheral blood mononuclear cells from 19 CRF01_AE-infected and 9 B-infected subjects were tested at early (0 or 1 month, designated TE) and late (8, 12 or 16 months, designated setpoint or TL) time points after seroconversion using IFN-γELISPOT assays and vaccinia recombinant viruses expressing E or B Env, Gag, Nef or Pol.

RESULTS: At TE, cross-reactive responses to one or more proteins were seen in 84% of E and 78% of B-infected subjects. A higher number of cross-reactive T cells were seen in E-infected subject than in B-infected subjects. Cross-reactivity to Pol dominated. While cross-clade responses declined with time, they were maintained. No correlation was observed between viral loads or CD4 and T cell responses.<IMG SRC="images/prog/A10150_IMG1.jpg" border=0>Conclusion Most HIV-1 subtype E-and B-infected subjects had cross-reactive T cell responses that persisted with time. Subtype E-infected subjects mounted a stronger immune response, likely reflecting their higher early viral load compared to B-infected subjects. These data suggest that HIV-1 subtype E-or B-based vaccines may raise cross-reactive T-cell responses.

Keywords: AEGIS, HIV Seropositivity, Acquired Immunodeficiency Syndrome, HIV-1, HIV Infections, T-Lymphocytes, Viral Load, Thailand, Superinfection, Cohort Studies, Prospective Studies

040711
A10150