Maternal humoral factors associated with perinatal human immunodeficiency virus type-1 transmission in a cohort from Kigali, Rwanda, 1988-1994

Objectives: to study different parameters of humoral immunity responses in the serum of 39 human immunodeficiency virus type-1 infected pregnant women from Kigali, (Rwanda) in correlation with perinatal transmission. Methods: this study was done between 1988 and 1994. Thirty nine HIV-1 infec ted women, 18 transmitting (T) and 21 non-transmitting (NT) mothers, have b een chosen based on the quantity of sera available for analysis, Maternal d ata were collected at the time of delivery or during the preceding month. Q uantification of viral load was performed by the signal amplification bDNA assay Specific reactivity of antibody was tested against recombinant p24 pr otein and five different synthetic peptides from gp120 and gp41 based on HI V LAI-strain sequences. Neutralization assays were performed against labora tory (RII strain of the HIV-1 C subtype) and primary strains (two NSI and o ne SI of the HIV-I A subtype). Antibody Dependent Cellular Cytotoxicity ass ay was performed with CEM.NKR cells against a laboratory HIV-1 strain. Results: absence of correlation regarding maternal viral load, or viral sub type and vertical transmission was observed, By contrast, the CD4/CD8 ratio was significantly higher in non-transmitting mothers compared to transmitt ing mothers, Moreover, high anti-p24 antibody avidity was correlated with a lower risk of perinatal transmission. Furthermore, transmission risk appea red significantly higher with reactivity of serum samples to linear epitope s of gp41 (amino acids 566-582, 578-594), whereas risk appeared lower with reactivity to the immunodominant domain of gp41 (amino acids 597-609). No s ignificant difference was observed in titres of antibody neutralizing prima ry isolates (two NSI (non syncitium inducer) and one SI (syncitium inducer) of the HIV-1 A subtype) and laboratory strain (RII strain, of the HIV-I C subtype) between transmitting and non-transmitting mother's sera, In additi on, titres of Antibody Dependent Cellular Cytotoxicity were similar in tran smitting versus non-transmitting mothers. However, high Antibody Dependent Cellular Cytoxicity titres were correlated with a good clinical status of c hildren. Conclusions: three parameters such as high CD4/CD8 ratio, high anti-p24 ant ibody avidity and high reactivity against the immunodominant epitope of gp4 1 have been shown to be correlated with no perinatal transmission. High Ant ibody Dependent Cellular Cytotoxicity titres appeared to be linked to a goo d clinical status of children after birth. One parameter, reactivity agains t two linear epitopes of gp41, appeared to be correlated with vertical tran smission. (C) 1999 The British Infection Society.