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Abstract
MATERNAL VIRAL DIVERSITY, V3 ANTIBODIES AND THE VERTICAL TRANSMISSION OF HIV-1 SUBTYPE C.
GUEVARA H, TIEN P, JOHNSTON E, ZIJENAH L, CONTAG C, HENDRY M, KATZENSTEIN D
Background: Increased diversity in the envelope (env) V3 region of HIV has been associated with clinical non-progression and reduced mother to child transmission (MTCT). Diversity of maternal virus due to immune selection is countered by viral escape through env gene mutation. Diversity in virus is associated with a more heterogeneous immune response (HIR).
Objective: To quantify maternal virus replication, diversity and env antibody in relationship to MTCT of HIV-1 subtype C in Zimbabwe.
Methods: HIV-1 RNA, env viral heterogeneity, and V3 env antibodies were studied in serum from 39 women (selected as those with virus load > 30,000 copies/ml); 19 did not transmit (NTX) and 20 transmitted (TX) the infection to their infants.
Maternal plasma RNA was quantified by PCR Amplicor; env heterogeneity was expressed as Entropy values derived from heteroduplex mobility assay (HMA) gels of (C2-C5) RT PCR cDNA. High avidity antibodies were assayed with V3 peptides to the homologous C and heterologous subtypes (A, B, F, G, and MN) to measure HIR to V3 region.
Results: Mean antibody titers to env V3 subtype C were higher in Tx vs NTX (p=0.007). Maternal HIV-1 RNA, Entropy (viral divergence) and HIR mean values were not different between TX and NTX. However, there was significant correlation between increased viral env heterogeneity, HIV RNA levels (r = 0.47, p= 0.0032) and HIR (r = 0.42, p =0.008). This association was greater among the NTX (r =0.68, p = 0.0017) for viral heterogeneity and (r = 0.5, p = 0.035) for HIR.
Conclusions: High and narrow maternal env V3 maternal antibody responses to homologous subtype C peptide were associated MTCT. Increased viral divergence and antibody heterogeneity among non-transmitting women with high virus load suggests that broadly reactive HIR and greater viral diversity are protective. Vaccine strategies to reducing MTCT should include multiple envelope subtypes and variants to elicit a broad humoral immune response.
The 1st. IAS Conference on HIV Pathogenesis and Treatment
Abstract no.
131
Suggested Citation
"GUEVARAH, et al.
MATERNAL VIRAL DIVERSITY, V3 ANTIBODIES AND THE VERTICAL TRANSMISSION OF HIV-1 SUBTYPE C..
Oral Presentation:
The 1st. IAS Conference on HIV Pathogenesis and Treatment
:
Abstract no.
131"
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