American Academy of Pediatrics Section on Uniformed Services 2014 Scientific Awards Competition

Background: Perinatal HIV transmission accounts for the majority of pediatric HIV infections. Little is known about the HIV-1 immune characteristics governing maternal to child transmission. V2-specific antibodies have been associated with protection against perinatal transmission and recently were identified as a potential correlate of protection in the RV144 vaccine trial. We sought to evaluate the role of these antibodies in perinatal transmission utilizing a bank of stored maternal and infant samples from a previous perinatal HIV study. Methodology: 181 HIV-infected pregnant women from Thailand were enrolled between 1996 and 1998. 102 did not receive antiretroviral drugs and their samples were included in our study. 18 transmitting mothers (TM) were paired with 18 non-transmitting mothers (NTM) based on viral load and CD4 percentage at time of delivery. Infants of these mothers had samples collected at 6 months of life which were also analyzed. IgG binding antibodies specific to cyclic V2 peptides 92THO23 and MN, and gp70V1V2 Case A2 and A/E protein, were measured in the serum samples by ELISA. Endpoint titers of TM were compared with those of NTM using the Wilcoxon signed-rank test. Results: There were no significant differences in the maternal binding titers of V2specific IgG to both cyclic V2 peptide (92THO23, MN) and gp70V1V2 protein (Case A2 and A/E) between TM and NTM. Compared to HIV uninfected infants, HIV positive infants of TM were found to have significantly higher levels of V2-specific IgG antibodies to the cyclic V2 peptides 92THO23 (p<.001) and MN (p<.001), as well as to gp70V1V2 Case A2 protein (p<.001) and Case A/E protein (p=.0015). Conclusions: We found no differences in the IgG antibody binding titers specific to cyclic V2 peptides or to gp70V1V2 proteins between TM and NTM. HIV positive infants of TM did have significantly higher IgG binding titers to both cyclic V2 peptides, and gp70V1V2 proteins. However, at 6 months of life, this is likely indicative of the child’s developing immune response to HIV-1 infection, and a waning of maternal antibody in uninfected infants. Although we only tested a small number of HIV-1 transmitting pairs, our data suggest that V2-specific IgG antibodies may not play a role in mother to child transmission. Corresponding Author Name Daniel J Adams Rank/Service Capt/USAF Secondary Author Names and Ranks: Sodsai Tovanabutra, PhD, civilian Anjali Kunz, MD, MAJ, USA Panita Pathipvanich, MD, civilian Kriengkrai Srithanaviboonchai, MD, MPH, civilian Abraham Pinter, PhD, civilian Nelson Michael, MD, PhD, COL, USA Jerome Kim, MD, COL, USA Mangala Rao, PhD, civilian Merlin Robb, MD, LT COL (ret), USA