title: Effects of helminths and Mycobacterium tuberculosis infection on HIV-1:  a cellular immunological perspective.
abstract: OBJECTIVE
  In many regions of the world, a high prevalence of HIV-1, helminthic and Mycobacterium tuberculosis (Mtb) infections can be found. Here, we summarize the types of immune responses induced and/or modulated by these pathogens and the consequences for HIV-1 disease.
  
  
  RESULTS
  Helminths predominantly induce strong T helper (Th) 2 cellular responses which are downregulated in chronic disease. The anatomical niche populated by helminths plays a key factor in the effect these parasites have on HIV-1 transmission and subsequent replication. Gut-associated helminths have been found to increase HIV-1 transmission via the lesions they provide. In spite of this, the many immune modulatory molecules secreted by the parasites may inhibit or slow HIV-1 infection. In contrast, Mtb is mainly restricted to the lung and the Mtb-specific Th cells induced are highly susceptible to HIV-1 infection and replication. Antigens from both pathogens have immunomodulatory activity that can skew cellular immune responses in specific directions.
  
  
  CONCLUSIONS
  The effect of helminths and Mtb on modulating immune responses is varied and complex with both their location and phenotype potentially influencing HIV-1 disease. These pathogens have evolved a complex array of molecules which have the capacity to modulate immunity and preserve pathogen survival.
authors.affiliation: Laboratory of Experimental Virology, Department of Medical Microbiology, Centre for Infection and Immunity, Academic Medical Centre of the University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Emily E I M
authors.initials: EE
authors.lastname: Mouser
authors.forename: Georgios
authors.initials: G
authors.lastname: Pollakis
authors.forename: William A
authors.initials: WA
authors.lastname: Paxton
mesh_terms: D000818:Animals; D060085:Coinfection / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology / Q000821:virology; D015658:HIV Infections / Q000150:complications / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology; D006373:Helminthiasis / Q000150:complications* / Q000276:immunology / Q000469:parasitology; D006376:Helminths / Q000276:immunology*; D054884:Host-Pathogen Interactions / Q000276:immunology; D006801:Humans; D056747:Immunomodulation; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D014376:Tuberculosis / Q000150:complications* / Q000276:immunology / Q000382:microbiology