Tuberculosis detection in nonhuman primates is enhanced by use of testing algorithms that include an interferon-γ release assay

Abstract

OBJECTIVE To develop a testing algorithm that incorporates multiple assays to evaluate host cellular and humoral immunity and antigen detection concerning Mycobacterium tuberculosis complex (MTBC) infection in captive nonhuman primates. ANIMALS Cohorts of captive-bred and wild-caught macaques from 5 different geographic regions. PROCEDURES Macaques were tested for MTBC infection by use of a γ interferon tuberculosis (GIFT) assay, an interferon-γ release assay, and other assays. In the first 2 cohorts (n = 15 and 181), initial validation of the GIFT assay was performed by use of experimentally infected and unexposed control macaques. In the next 3 cohorts (n = 59, 42, and 11), results were obtained for opportunistically collected samples from macaques exposed during spontaneous outbreaks. RESULTS Sensitivity and specificity of the GIFT assay in the control cohorts were 100% and 97%, respectively, and were variable but enhanced by incorporating results from multiple assays in spontaneous outbreaks. CLINICAL RELEVANCE The detection and management of MTBC infection in captive nonhuman primate populations is an ongoing challenge, especially with animal imports and transfers. Despite standardized practices of initial quarantine with regular intradermal tuberculin skin testing, spontaneous outbreaks continue to be reported. Since infection encompasses a range of disease manifestations over time, a testing algorithm that incorporates multiple assays, such as the GIFT assay, to evaluate host cellular and humoral immunity in addition to agent detection is needed. Testing a combination of samples from controlled studies and spontaneous outbreaks of MTBC infection in nonhuman primates would advance the development and validation of a functional algorithm that incorporates promising tools such as the GIFT assay.

New gamma interferon (IFN-γ) algorithm for tuberculosis diagnosis in cynomolgus macaques

“…TB is designated as the first infectious disease that must be screened and infected macaques must be removed from the colony immediately. Among various TB detection tools, IGRA is acceptable as a method to detect early TB infection and the latent period [11, 12]. As such, the monkey IGRA assay was developed [16].…”

“…Although the antibody blood test such as ELISA was developed, the humoral-mediated immune response appeared after the cell-mediated immune response, leading the TST and/or IGRA to be kept as preferable methods in many primate facilities [11] [12].…”

“…Molecular techniques such as IS 6110 nested PCR or X-pert took a shorter time, but could not detect the immune response. Although the antibody blood test such as ELISA was developed, the humoral-mediated immune response appeared after the cell-mediated immune response, leading the TST and/or IGRA to be kept as preferable methods in many primate facilities [11] [12].…”

“…The copyright holder for this preprint this version posted April 4, 2024. ; https://doi.org/10.1101/2024.04.04.588038 doi: bioRxiv preprint testing algorithm that incorporates multiple assays; for example, culture, molecular technique, antibody blood test, tuberculin skin test (TST), and interferon gamma release assay (IGRA), was suggested to improve overall sensitivity and specificity [9][10][11]. MTBC culture (directly detected MTBC) is supposed to be a gold standard method in humans, but it was inconvenient for routine screening in a large number of captive monkeys.…”

Outbreak of Mycobacterium orygis in a Shipment of Cynomolgus Macaques Imported from Southeast Asia — United States, February–May 2023

“…TST using mammalian old tuberculin is an important component of current import surveillance, but it is an imperfect test, subject to both false-positive and false-negative results ( 8 ). A testing protocol that incorporates multiple different tests has been suggested as a potential way to improve sensitivity and specificity ( 9 , 10 ) but, to date, no such protocol has been validated. Rigorous occupational safety and health programs based on the hierarchy of controls (i.e., elimination, substitution, engineering controls, administrative controls, and personal protective equipment) § will remain critical to protect NHP workers, especially those who have close contact with imported NHP.…”