Early Sites of Virus Replication After Oral SIV_mac251 Infection of Infant Macaques: Implications for Pathogenesis

Abstract

Despite optimization of preventative measures for vertical HIV-1 transmission, daily, roughly 400 infants become HIV infected, most of them through breastfeeding. Viral entry has been presumed to occur in the gastrointestinal tract; however, the exact entry site(s) have not been defined. Therefore, we quantified simian immunodeficiency virus (SIV) RNA and DNA in oral, intestinal, and systemic tissues of 15 infant macaques within 48-96 h after oral SIV exposure. SIV DNA was detected as early as 48 h, whereas SIV RNA was typically detected at later time points (72-96 h). Transmitted founder viruses were identical or very similar to a single genotype in the SIV challenge stock. SIV RNA and DNA were most frequently found in lymph nodes (LNs) draining the oral cavity and in the ileum. Using in situ hybridization, SIV-infected cells in LNs were exclusively represented by CD3 T cells. SIV RNA and DNA were also detected in the lungs of 20% of the animals, and 60% of the animals had detectable SIV DNA in the cerebrum. The early detection of viral RNA or DNA in lung and brain tissues emphasizes the need for early treatment of pediatric HIV infection to prevent damage not only to the immune system but also to the respiratory tract and central nervous system.

Analytical Treatment Interruption after Short-Term Antiretroviral Therapy in a Postnatally Simian-Human Immunodeficiency Virus-Infected Infant Rhesus Macaque Model

“…ISH. Formalin-fixed, paraffin-embedded tissue sections were seqentially cut (5 m) and stained for CD3 and CD20 (Table S2) as previously described (67,68). SHIV RNA was visualized with a 1-plex ViewRNA in situ hybridization (ISH) tissue assay kit using SIV mac239 or beta-actin (positive control) probe sets and a ViewRNA chromogenic signal amplification kit (Thermo Fisher, Waltham, MA).…”

Oral clade C SHIV challenge models to study pediatric HIV-1 infection by breastmilk transmission

“…In transmission studies, the evaluation of T/F viruses is hampered by the limited genetic diversity. Although SIV mac251 is an uncloned viral swarm, the genetic diversity within each stock is often low and variable among different SIV mac251 challenge stocks because of prior histories of propagation (22, 34, 45). In addition, due to significant differences in envelope between SIVmac (which is similar to HIV-2) and HIV-1, the use of the oral pediatric SIV mac251 infection model also has limited translational potential for HIV vaccine studies assessing the role of HIV Env-specific antibody responses in vaccine-mediated protection against HIV acquisition.…”

“…Detection of virally-infected cells in lymph node sections: Sequential sections (5 µm) of formalin-fixed, paraffin-embedded lymph nodes were cut and stained for CD3 and CD20 as previously described (22, 35). SHIV RNA was visualized with the 1-Plex ViewRNA ™ ISH Tissue Assay Kit using SIV mac239 or Beta actin (positive control) probe sets that were dectected via the ViewRNA ™ Chromogenic Signal Amplification Kit (all from ThermoFisher, Waltham, MA).…”

Lack of susceptibility in neonatally infected rhesus macaques to simian immunodeficiency virus-induced encephalitis

“…It is therefore hard to argue whether the virus entered the brains of the neonates more easily because they lacked the BBB and therefore the Trojan horse model may not be necessary. While it is widely accepted that virus enters the brain within 14 days, recent studies using orally infected neonatal animals have detected viral RNA in the brain of an animal, 96 h after initial exposure (Amedee et al 2018). However, 40% of infants had detectable viral DNA in at least one tissue 48 h after exposure, and more at 72 and 96 h respectively, demonstrating the wide variability of animal and infectious differences in neonatal rhesus macaques.…”