The role of virologic and immunologic factors in mother-to-child transmission of HIV-1.
OBJECTIVE
More than 90% of human immunodeficiency virus type 1 (HIV-1) infection in children is acquired by mother-to-child transmission. However, infection of the child occurs in between 14 and 35% of cases.


METHODS
To understand the mechanisms involved in HIV-1 transmission, we have investigated the antigenic, molecular, and phenotypic characteristics of the virus harbored in infected mothers and their children.


RESULTS
A clear correlation was observed between the transmission of the virus and the isolation of viral variants with a rapidly replicating and syncytium-inducing phenotype from the mother. Furthermore, non-transmitting mothers were able to neutralize several primary isolates more frequently than transmitting mothers. The comparison of the viral phenotype and genotype of mother-child pairs showed that the transmitted virus did not have common features, suggesting that transmission is usually not a selective process.


CONCLUSIONS
This study suggests that transmission is governed by an interaction of both viral and immunological factors. The results obtained indicate that different strategies can be applied for the prevention of transmission.
Colognesi
C
C
Unit of Immunobiology of HIV, DIBIT, San Raffaele Scientific Institute, Milano, Italy.
Halapi
E
E
Jansson
M
M
Hodara
V
V
Steuer
G
G
Tresoldi
E
E
Leitner
T
T
Scarlatti
G
G
D000940:Antigenic Variation; D003588:Cytopathogenic Effect, Viral; D005260:Female; D015483:HIV Antibodies / Q000097:blood; D015488:HIV Antigens / Q000235:genetics; D015658:HIV Infections / Q000150:complications* / Q000276:immunology / Q000635:transmission*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008431:Maternal-Fetal Exchange / Q000276:immunology; D009500:Neutralization Tests; D010641:Phenotype; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology* / Q000821:virology*; D012307:Risk Factors; D014779:Virus Replication
D015483:HIV Antibodies; D015488:HIV Antigens