title: Plasmodium vivax parasites alter the balance of myeloid and plasmacytoid dendritic cells and the induction of regulatory T cells.
abstract: Immunity induced by Plasmodium vivax infections leads to memory T-cell recruitment and activation during subsequent infections. Here, we investigated the role of regulatory T cells (Treg) in coordination with the host immune response during P. vivax infection. Our results showed a significant increase in the percentage of FOXP3+ Treg, IL-10-secreting Type I Treg (Tr1) and IL-10 levels in patients with acute P. vivax infection as compared with those found in either naïve or immune controls. The concurrent increase in the Treg population could also be reproduced in vitro using peripheral blood mononuclear cells from naïve controls stimulated with crude antigens extracted from P. vivax-infected red blood cells. Acute P. vivax infections were associated with a significant decrease in the numbers of DC, indicating a general immunosuppression during P. vivax infections. However, unlike P. falciparum infections, we found that the ratio of myeloid DC (MDC) to plasmacytoid DC (PDC) was significantly lower in acute P. vivax patients than that of naïve and immune controls. Moreover, the reduction in PDC may be partly responsible for the poor antibody responses during P. vivax infections. Taken together, these results suggest that P. vivax parasites interact with DC, which alters the MDC/PDC ratio that potentially leads to Treg activation and IL-10 release.
authors.affiliation: Department of Clinical Microbiology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand. oadworld@yahoo.com
authors.forename: Kulachart
authors.initials: K
authors.lastname: Jangpatarapongsa
authors.forename: Patchanee
authors.initials: P
authors.lastname: Chootong
authors.forename: Jetsumon
authors.initials: J
authors.lastname: Sattabongkot
authors.forename: Kesinee
authors.initials: K
authors.lastname: Chotivanich
authors.forename: Jeeraphat
authors.initials: J
authors.lastname: Sirichaisinthop
authors.forename: Sumalee
authors.initials: S
authors.lastname: Tungpradabkul
authors.forename: Hajime
authors.initials: H
authors.lastname: Hisaeda
authors.forename: Marita
authors.initials: M
authors.lastname: Troye-Blomberg
authors.forename: Liwang
authors.initials: L
authors.lastname: Cui
authors.forename: Rachanee
authors.initials: R
authors.lastname: Udomsangpetch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D016753:Interleukin-10 / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation; D016780:Malaria, Vivax / Q000276:immunology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D010966:Plasmodium vivax / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
chemical_list: D000953:Antigens, Protozoan; D016753:Interleukin-10