Replicating Ad-SIV recombinant vaccines elicit mucosal humoral immunity in rhesus macaques at both rectal and vaginal sites with potential protective efficacy

Autor: Christopher James Hogge, Sabrina Helmold Hait, Gospel Enyindah-Asonye, Zuena Mushtaq, Tanya Hoang, Marjorie Robert-Guroff
Rok vydání: 2019
Předmět:
Zdroj: The Journal of Immunology. 202:72.2-72.2
ISSN: 1550-6606
0022-1767
DOI: 10.4049/jimmunol.202.supp.72.2
Popis: Humoral immunity, especially at mucosal sites, is important for preventing HIV acquisition. Replicating adenovirus (Ad)-SIV priming/gp120 boosting regimens have elicited mucosal immunity and protection against intrarectal SIV challenge in Rhesus macaques. Here we investigated mucosal responses in female macaques primed intranasally/orally, then intratracheally with Ad5hr-SIV(Env/gag/nef), boosted twice intramuscularly with SIV gp120, and challenged vaginally with repeated low-dose SIVmac251. Vaginal washes and rectal swabs and biopsies were obtained 3-weeks post-immunizations. gp120-specific antibodies were assayed by ELISA and memory B-cells by flow cytometry. Gp120-specific rectal memory B-cells increased post-Ad priming but waned post-boosting, whereas rectal and vaginal antibodies increased post-boosting. Compared to pre levels, rectal gp120-specific IgA (p = 0.011) and IgG (p< 0.0001) were elevated post-2nd boost; vaginal IgA/IgG antibodies differed post-1st boost (both p IgA post-2nd boost (p=0.001). Rectal memory B cells post- 1st and 2nd Ads positively correlated with gp120-specific rectal IgA (p = 0.015, p = 0.0013, respectively) post-1st Ad, indicating vaccine targeting to mucosal effector sites. Significantly delayed SIV acquisition was not seen, but vaginal IgG post-1st Ad correlated with number of challenges (p=0.029). Vaccinated animals had lower acute viremia than controls (p = 0.054), consistent with higher vaginal gp120-specific IgG 2 weeks post-infection (p < 0.0001). Our data show that upper respiratory tract immunization with replicating Ad vectors elicits strong mucosal immunity with potential protective efficacy against rectal/genital transmission.
Databáze: OpenAIRE
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