HIV infection and specific mucosal immunity: workshop 4B

Oral innate immunity in HIV infection in HAART era

Oral innate immunity, an important component in host defense and immune surveillance in the oral cavity, plays a crucial role in the regulation of oral health. As part of the innate immune system, epithelial cells lining oral mucosal surfaces not only provide a physical barrier but also produce different antimicrobial peptides, including human β-defensins (hBDs), secretory leukocyte protease inhibitor (SLPI), and various cytokines. These innate immune mediators help in maintaining oral homeostasis. When they are impaired either by local or systemic causes, various oral infections and malignancies may be developed. Human immunodeficiency virus (HIV) infection and other co-infections appear to have both direct and indirect effects on systemic and local innate immunity leading to the development of oral opportunistic infections and malignancies. Highly active antiretroviral therapy (HAART), the standard treatment of HIV infection, contributed to a global reduction of HIV-associated oral lesions. However, prolonged use of HAART may lead to adverse effects on the oral innate immunity resulting in the relapse of oral lesions. This review article focused on the roles of oral innate immunity in HIV infection in HAART era. The following five key questions were addressed: (i) What are the roles of oral innate immunity in health and disease?, (ii) What are the effects of HIV infection on oral innate immunity?, (iii) What are the roles of oral innate immunity against other co-infections?, (iv) What are the effects of HAART on oral innate immunity?, and (v) Is oral innate immunity enhanced by HAART?

Role of maternal, transplacentally acquired HIV-1-specific neutralizing antibodies in protecting the uninfected offspring against HIV-1 transmission via breast milk

Evaluation of: Lynch JB, Nduati R, Blish CA et al. The breadth and potency of passively acquired human immunodeficiency virus type 1-specific neutralizing antibodies do not correlate with the risk of infant infection. J. Virol. 85(11), 5252–5261 (2011). HIV-1-infected pregnant women may transfer anti-HIV-1 antibodies, at varying lengths, extents and specificities, to their babies during pregnancy via the placenta and after birth via breast milk. In vitro, most antibodies to many viral and bacterial agents, present at birth in the infant serum, are protective, but it is unclear whether the magnitude and breadth of the maternal passively acquired HIV-1-specific neutralizing antibodies constitute, in fact, a predictor variable of protection against mother-to-child HIV-1 transmission via breast milk. In their article, Lynch et al. addressed the issue using a rich source of repository samples from a cohort of pregnant women infected with HIV-1, enrolled before the availability of widespread antiretroviral treatment and management measures of intervention. This type of treasured samples enables us to dissect the significance of maternal passively acquired HIV-1-specific serum antibodies in highly exposed HIV-1-uninfected children for protection against HIV-1 infection via breast milk. Results showed no significant difference in breadth and potency of in vitro neutralizing antibodies between children who became HIV-1 infected and children who remained uninfected throughout the study period. The authors concluded that neither the breadth nor the potency of passively acquired HIV-1-specific neutralizing antibodies correlate with the risk of HIV-1 acquisition via breast milk. The study raises intriguing possibilities to speed the process of refining both in vitro methods to identify protective antibody responses and vaccine development strategies relevant at oral and gastrointestinal mucosal sites.