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Interactions between simian immunodeficiency virus and Mycobacterium leprae in experimentally inoculated rhesus
B J Gormus1, M Murphey-Corb, L N Martin
1Delta Regional Primate Research Center, Tulane University, Covington, Louisiana 70433.
Abstract:
Thirty-four rhesus monkeys were inoculated with Mycobacterium leprae inoculum isolated from sooty mangabey monkeys with leprosy. Later it was learned that one of the M. leprae-donor mangabeys was asymptomatically infected with simian immunodeficiency virus (SIV). Thus, five of the rhesus monkey were coinoculated with M. leprae and SIV. Three of the five became SIV-positive and developed signs of leprosy and an AIDS-like illness. Two animals remained healthy. The coinoculated leprosy-positive rhesus monkeys developed leprosy despite serologic response patterns to M. leprae antigens that usually indicate leprosy resistance. Three (60%) of the five SIV-positive rhesus monkeys developed leprosy compared with 21% of the animals who received SIV-free M. leprae inocula. Diminished lepromin skin test responses and decreasing T-helper cell percentages were observed in SIV-coinoculated rhesus monkeys with leprosy. These observations suggest that SIV increases the susceptibility of rhesus monkeys to leprosy, possibly related to loss of T-helper cell function.
Insights
Simian immunodeficiency virus (SIV) coinfection significantly increased leprosy development in rhesus monkeys. SIV-positive monkeys showed reduced immune responses, suggesting SIV impairs leprosy resistance.
Area of Science:
- Primate immunology
- Infectious diseases
- Mycobacterium leprae research
Background:
- Leprosy, caused by Mycobacterium leprae, affects various primate species.
- Simian immunodeficiency virus (SIV) is a lentivirus that can cause an AIDS-like illness in macaques.
- The interaction between M. leprae and SIV coinfection in non-human primates is not well understood.
Purpose of the Study:
- To investigate the effect of SIV coinfection on the susceptibility of rhesus monkeys to M. leprae.
- To examine immune responses in rhesus monkeys coinfected with M. leprae and SIV.
Main Methods:
- Thirty-four rhesus monkeys were inoculated with M. leprae.
- Five rhesus monkeys were coinoculated with M. leprae and SIV from an asymptomatically infected donor.
- Leprosy development, SIV status, lepromin skin test responses, and T-helper cell percentages were monitored.
Main Results:
- Three out of five (60%) SIV-positive rhesus monkeys developed leprosy, compared to 21% of SIV-negative controls.
- SIV-coinfected monkeys with leprosy showed diminished lepromin skin test responses and decreased T-helper cell percentages.
- Leprosy developed in coinfected animals despite serologic responses typically indicating resistance.
Conclusions:
- SIV coinfection increases the susceptibility of rhesus monkeys to M. leprae infection.
- The increased susceptibility may be linked to SIV-induced loss of T-helper cell function.
- This study highlights the impact of viral coinfection on susceptibility to bacterial diseases.