U42 AR Supplement: SNPRC Proposal to expand U42 rhesus monkey holding and Production. Abstract The Southwest National Primate Research Center (SNPRC) has developed an SPF Indian-derived (ID) rhesus colony, supported by the NIH SPF rhesus breeding program (U42 OD010442). HIV/AIDS research at the center strongly supports both internal and external scientists whose work investigates critical topics including, but not limited to, Mtb/HIV coinfection, development of nanoparticle vaccines against SIV/HIV, HIV/SHIV infection in newborn rhesus monkeys, role of miRNA’s in gastrointestinal dysfunction in the HIV/SIV rhesus model, the investigation of CNS myeloid cells as chronic reservoirs in SIV-infected primates, and the development of host- directed therapies against SIV/HIV and Mtb/HIV infection. There has been a critical shortage of these primates for research for over a decade. The sudden usage of rhesus macaques for COVID-19 research—necessitated by the pandemic—has created further strain on the availability of this primate model for HIV/AIDS research [NOT- OD-20-173. September 11, 2020 ‘Notice of Limited Availability of Research Nonhuman Primates’]. In order to meet urgent needs for recent COVID-19 research, SNPRC rhesus macaques, over the past year, have been mostly directed to these studies as required by Operation Warp Speed and directives put forth from the NIH. This has severely impacted our ability to maintain research primates for our HIV/AIDS investigators under the U42 funding. There is an acute, urgent need to increase production of these U42 SPF Indian-derived primates. This application proposes to increase holding and breeding space at the SNPRC to support expansion of this colony.