William A. Paxton
In vitro findings published in PLOS Pathogens showed that Schistosoma mansoni antigens have the ability to reduce HIV infection and replication, suggesting that coinfection with parasitic helminths stimulates an immune response that may reduce HIV transmission or disease, researchers reported.
“Many people in the world are infected with HIV and at the same time coinfected with a large array of other pathogens — bacteria, fungus, yeast, viruses and parasites. These other pathogens will have the capacity to induce immune responses which could either result in increased virus infection/replication or perhaps decreased infection/replication,” William A. Paxton, PhD, DIC, chair in infection and global health and professor in the department of clinical infection, microbiology and immunology at the University of Liverpool’s Institute of Infection and Global Health, explained to Infectious Disease News.
“Parasites, and specifically helminths, have been well documented to dampen the immune response mounted against them as a way of escaping their effects and promoting their survival. We therefore aimed in this study to identify whether Schistosoma mansoni parasite antigens had the capacity to modulate immune responses that could affect HIV-1 infection and/or replication.”
The researchers analyzed in vitro the effect that an extract from S. mansoni eggs called soluble egg antigen (SEA) had on HIV infection, and studied two cloned antigens within SEA, kappa-5 and omega-1. As Paxton explained, they assessed the interaction of parasite antigens with dendritic cells, “a cell type known to orchestrate the immune responses mounted against specific pathogen antigen.”
“HIV-1 is known to interact with dendric cells and this interaction can lead to enhanced virus infection and replication,” Paxton said. “We studied two aspects: 1) the direct interaction of parasite antigen with dendritic cells; and 2) whether antigens could result in a stimulated immune response with different infectivity profiles with HIV-1.”
The researchers observed a binding between kappa-5 and dendritic cells that prevented HIV-1 from subsequent CD4 cell replication. Moreover, they found that omega-1 stimulated T cells, resulting in reduced viral infection/replication.
“The results help to unravel the complex interactions that exist between different pathogens, here helminths and HIV,” Paxton said. “Understanding these interactions will provide a way to better understand how we may be able to modulate immune responses so that the effects of HIV infection can be reduced or limited.”
He underscored the need for further research.
“Better understanding the precise mechanism and molecular events that lead to this dampening of immune responses would point toward new ways to modulate immune responses in HIV-infected individuals in order to mimic the observed effects,” Paxton said. “Understanding the complex interaction of copathogens with HIV will indicate which infections should be more rigorously and preferentially treated in coinfected people.” – by Marley Ghizzone
Disclosures: The authors report no relevant financial disclosures.