AEGiS-13IAC: HIV-specific T-helper cell responses in infants of HIV-infected mothers exposed or not to anti-retroviral treatment.

13th International AIDS Conference

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

HIV-specific T-helper cell responses in infants of HIV-infected mothers exposed or not to anti-retroviral treatment.

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. TuOrA282)

Kuhn L, Coutsoudis A, Meddows-Taylor S, Mngqundaniso N, Trabattoni D, Clerici M, Shearer G, Tiemessen C, Gray G
L. Kuhn, Columbia University, Sergievsky Center, 630 W 168th Street, New York, United States, Tel.: +1 212 305 2398, Fax: +1 212 305 2426, E-mail: lk24@columbia.edu

BACKGROUND: Acquired HIV-specific cell-mediated immune responses are observed in some HIV-exposed but uninfected individuals, and it has been inferred, but not demonstrated, that these responses constitute a part of natural protective immunity to HIV. The context of maternal-infant transmission in breast-feeding populations offers a unique natural exposure setting in which to test empirically and prospectively whether or not these acquired cellular immune responses to HIV can protect against subsequent HIV challenge.

METHODS: We measured T-helper cell responses to HIV envelope peptides and other antigens in cord blood of 86 infants in Durban and 29 infants in Soweto of HIV-positive women who received no anti-retroviral treatment, and among 41 infants exposed to short-course ZDV-3TC prophylaxis in Soweto. Cord blood samples from 23 infants of HIV-negative women were tested as controls. Infants were followed with serial HIV RNA tests to establish HIV infection.

RESULTS: In the absence of anti-retroviral treatment, T-helper cell responses to HIV envelope peptides were detected among 38% (Durban) and 24% (Soweto) of cord blood samples from HIV-positive women, but among no cord blood samples from HIV-negative women. No child with a T-helper cell response to HIV in cord blood and without evidence of HIV infection on the day of birth was found to acquire HIV infection on later testing through to 18 months, compared to 17% of infants with no HIV-specific response (p = 0.02). Exposure to ZDV-3TC significantly reduced the detection of these apparently protective cell-mediated responses to less than 2% (p = 0.007).

CONCLUSIONS: Cellular immune responses to HIV are frequently detected in uninfected newborns of untreated HIV-infected mothers and appear to provide complete protection against subsequent HIV transmission. Exposure to short-course ZDV-3TC given to prevent perinatal HIV transmission rapidly attenuates these important responses in the newborn.

Keywords: AEGIS, HIV, HIV Infections, T-Lymphocytes, Helper-Inducer, HIV Seropositivity, Zidovudine, Mothers, Lamivudine, Anti-HIV Agents, Breast Feeding, HIV Seronegativity, HIV Antigens, Fetal Blood, Infant, Human, Female, Child, Infant, Newborn, therapy, immunology
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