RESUMO
BACKGROUND: Acquired HIV-specific cell-mediated immune responses have been observed in exposed-uninfected individuals, and it has been inferred, but not demonstrated, that these responses constitute a part of natural protective immunity to HIV. This inference was tested prospectively in the natural exposure setting of maternal-infant HIV transmission in a predominantly breast-fed population. METHODS: Cord blood from infants of HIV-seropositive women in Durban, South Africa, were tested for in vitro reactivity to a cocktail of HIV envelope peptides (Env) using a bioassay measuring interleukin-2 production in a murine cell line. Infants were followed with repeat HIV RNA tests up to 18 months of age to establish which ones acquired HIV-infection. RESULTS: T-helper cell responses to Env were detected in 33 out of 86 (38%) cord blood samples from infants of HIV-seropositive women and in none of nine samples from seronegative women (P = 0.02). Among infants of HIV-seropositive mothers, three out of 33 with T-helper responses to Env were already infected before delivery (HIV RNA positive on the day of birth), two were lost to follow-up, and none of the others (out of 28) were found to be HIV infected on subsequent tests. In comparison, six out of 53 infants unresponsive to Env were infected before delivery, and eight out of 47 (17%) of the others were found to have acquired HIV infection intrapartum or post-partum through breast-feeding (P = 0.02). CONCLUSIONS: T-helper cell responses to HIV envelope peptides were detected in more than one-third of newborns of HIV-infected women; no new infections were acquired by these infants at the time of delivery or post-natally through breast-feeding if these T-helper cell responses were detected in cord blood.
Assuntos
Aleitamento Materno , Produtos do Gene env/imunologia , Soropositividade para HIV/imunologia , HIV-1/imunologia , Peptídeos/imunologia , Complicações Infecciosas na Gravidez/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Animais , Divisão Celular , Linhagem Celular , Células Cultivadas , Feminino , Sangue Fetal , Soropositividade para HIV/sangue , Soropositividade para HIV/transmissão , Humanos , Lactente , Recém-Nascido , Vírus da Influenza A/imunologia , Camundongos , Fito-Hemaglutininas/imunologia , Gravidez , Complicações Infecciosas na Gravidez/sangue , Estudos Prospectivos , Fatores de Risco , Linfócitos T Auxiliares-Indutores/citologia , Células Th1/citologia , Células Th1/imunologiaRESUMO
The aim of this study was investigate the HIV/AIDS/STI and TB knowledge, beliefs and practices of traditional healers in South Africa. In a cross-sectional study 233 traditional healers were interviewed in three selected communities in KwaZulu-Natal. Results indicate that the most common conditions seen were STIs, a variety of chronic conditions, HIV/AIDS (20%) and tuberculosis (29%). Although most healers had a correct knowledge of the major HIV transmission routes, prevention methods and ARV treatment, their knowledge was poorer on other HIV transmission routes, and 21% believed that there is a cure for AIDS. A minority reported unsafe practices in terms of reuse of razor blades on more than one patients and the reuse of enema equipment without sterilization, and two-thirds used gloves when carrying out scarifications. Randomized control trials are called for to test the effectiveness of traditional healing for HIV/AIDS, STI and TB prevention and care.
Assuntos
Síndrome da Imunodeficiência Adquirida/terapia , Conhecimentos, Atitudes e Prática em Saúde , Medicinas Tradicionais Africanas , Infecções Sexualmente Transmissíveis/terapia , Estudos Transversais , Cultura , Infecções por HIV/terapia , Humanos , Infecções Sexualmente Transmissíveis/transmissão , África do Sul , Tuberculose/terapiaRESUMO
Immunologic consequences of exposure to HIV-1 in utero are still poorly understood. This study investigates relationships between type-1 [interferon-gamma (IFN-gamma)] and type-2 (IL-10) cytokine production and maternal-infant HIV-1 transmission. Cord blood leukocytes from deliveries of 71 HIV-1-infected and 11 uninfected mothers were tested for in vitro IFN-gamma and IL-10 production after phytohemagglutinin (PHA) stimulation. The infants of these HIV-1-infected mothers were followed prospectively after birth to determine HIV vertical transmission, and IFN-gamma and IL-10 production was measured again at 6 mo. Median PHA-stimulated IFN-gamma production was 210 pg/mL in cord blood cells from infected and 73 pg/mL from uninfected mothers (p = 0.12), and median PHA-stimulated IL-10 production was 491 pg/mL in cord blood cells from infected and 161 pg/mL from uninfected mothers (p = 0.004). PHA-stimulated IFN-gamma and IL-10 production alone were not significantly associated with transmission, but relationships between the two cytokines differed among infected and uninfected infants of HIV-1-infected mothers. PHA-stimulated IFN-gamma and IL-10 production was positively correlated among infected (r = 0.7, p = 0.12 in cord blood and r = 0.66, p = 0.03 at 6 mo) but not uninfected infants, and stronger relative production of IFN-gamma to IL-10 was observed among exposed uninfected than among infected infants (p = 0.04). Exposure in utero to HIV-1 may augment production of IL-10 detectable in fetal cord blood. Stronger relative production of IFN-gamma to IL-10 in cord blood cells from infants of HIV-1-infected mothers may be associated with protection against perinatal HIV infection.
Assuntos
Infecções por HIV/imunologia , HIV-1 , Transmissão Vertical de Doenças Infecciosas , Interferon gama/sangue , Interleucina-10/sangue , Feminino , Sangue Fetal/química , Infecções por HIV/transmissão , Infecções por HIV/virologia , HIV-1/genética , HIV-1/fisiologia , Humanos , Recém-Nascido , Exposição Materna , Fito-Hemaglutininas/farmacologia , RNA Viral/sangue , Ensaios Clínicos Controlados Aleatórios como Assunto , Carga ViralRESUMO
Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) play a major role in control of viral replication. To understand the contribution of this antiviral response, an initial step is to fully define the specific epitopes targeted by CTL. These studies focused on CTL responses restricted by HLA-A*3002, one of the HLA-A molecules most prominent in African populations. To avoid the time-consuming effort and expense involved in culturing CTL prior to defining epitopes and restricting alleles, we developed a method combining Elispot assays with intracellular gamma interferon staining of peripheral blood mononuclear cells to first map the optimal epitopes targeted and then define the HLA restriction of novel epitopes. In two A*3002-positive subjects whose CTL responses were characterized in detail, the strongest response in both cases was to an epitope in p17 Gag, RSLYNTVATLY (residues 76 to 86). Using this method, CTL epitopes for which there were no motif predictions were optimized and the HLA restriction was established within 48 to 72 h of receipt of blood. This simple and convenient approach should prove useful especially in the characterization of CTL responses specific to HIV and other viruses, particularly in localities where performing cytotoxicity assays would be problematic.
Assuntos
Citocinas/análise , Epitopos de Linfócito T , HIV/imunologia , Antígenos HLA-A/fisiologia , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Citocinas/fisiologia , Humanos , Masculino , Dados de Sequência Molecular , Coloração e RotulagemRESUMO
Cytotoxic T-lymphocyte (CTL) activity plays a central role in control of viral replication and in determining outcome in cases of human immunodeficiency virus type 1 (HIV-1) infection. Incorporation of important CTL epitope sequences into candidate vaccines is, therefore, vital. Most CTL studies have focused upon small numbers of adult Caucasoid subjects infected with clade-B virus, whereas the global epidemic is most severe in sub-Saharan African populations and predominantly involves clade-C infection in both adults and children. In this study, sensitive enzyme-linked immunospot (elispot) assays have been utilized to identify the dominant Gag-specific CTL epitopes targeted by adults and children infected with clade-B or -C virus. Cohorts evaluated included 44 B-clade-infected Caucasoid American and African American adults and children and 37 C-clade-infected African adults and children from Durban, South Africa. The results show that 3 out of 46 peptides spanning p17(Gag) and p24(Gag) sequences tested contain two-thirds of the dominant Gag-specific epitopes, irrespective of the clade, ethnicity, or age group studied. However, there were distinctive differences between the dominant responses made by Caucasoids and Africans. Dominant responses in Caucasoids were more often within p17(Gag) peptide residues 16 to 30 (38 versus 12%; P < 0.01), while p24(Gag) peptide residues 41 to 60 contained the dominant Gag epitope more often in the African subjects tested (39 versus 4%; P < 0.005). Within this 20-mer p24(Gag), an epitope presented by both B42 and B81 is defined which represents the dominant Gag response in >30% of the total infected population in Durban. This epitope is closely homologous with dominant HIV-2 and simian immunodeficiency virus Gag-specific CTL epitopes. The fine focusing of dominant CTL responses to these few regions of high immunogenicity is of significance to vaccine design.