Immunity to Malaria in Plasmodium vivax Infection: A Study in Central China

Abstract

Background P. vivax infection is characterised by relapsing fever, indicating reinfection by previously hidden parasites in the host. Relapsed infection can lead to the activation of the memory T cell pool, which may lead to protective immunity. This study aims to characterise immune responses in acute P. vivax-infected patients living in an area of central China characterised by only P. vivax infection.Methodology/Principal FindingsWe conducted a cross-sectional immune-phenotypic analysis of adults using the following inclusion criteria: acute P. vivax infection (N = 37), a history of P. vivax infection (N = 17), and no known history of P. vivax infection (N = 21). We also conducted a 2-week longitudinal analysis following acute P. vivax infection, in which PBMC proliferation was measured in response to P. vivax and P. falciparum blood stage lysates. Using flow cytometry, we showed elevated memory T cells in the blood during acute P. vivax infection. The levels of γδ T cells were two-fold higher than those measured in naive controls. This result suggested that in the two populations, memory and γδ T cells promptly responded to P. vivax parasites. Interestingly, P. falciparum antigens stimulated T cells obtained from P. vivax-infected patients during a day 14-convalescence, whereas lymphocytes from the naïve control group responded to a lower degree of convalescence.Conclusions/SignificanceCell-mediated immunity during the convalescent period of the P. vivax-infected hosts was comprised of T cells that were specifically able to recognise P. falciparum antigens. Although the magnitude of the response was only half that measured after stimulation with P. vivax antigens, the matter of cross-antigenic stimulation is of great interest.

Immune responses during gestational malaria: a review of the current knowledge and future trend of research

“…Nevertheless, cell-mediated response seems unaffected as evidenced in studies during the convalescent period in P. vivax-infected hosts, thus confirming a T cell-specific response, which was also reactive to P. falciparum antigens [104,107].…”

“…In regions where different species of malaria parasites are endemic, it has been observed that immune response to P. falciparum interferes with the immune factors observed in P. vivax malaria [104] as confirmed by the strain-specific and serological crossreactive immunity between blood stage antigens of both species [5,105,106]. Nevertheless, cell-mediated response seems unaffected as evidenced in studies during the convalescent period in P. vivax-infected hosts, thus confirming a T cell-specific response, which was also reactive to P. falciparum antigens [104,107].…”

Low Immunogenicity of Neural Progenitor Cells Differentiated from Induced Pluripotent Stem Cells Derived from Less Immunogenic Somatic Cells

“…The co-culture experiments were carried out with slight modification as described [41], [66]. In detailed, 100 µl/well was set up as a volume system in 96-well plate.…”

Neural progenitor cells from human induced pluripotent stem cells generated less autogenous immune response

“…Cell viability was examined by trypan blue exclusion staining. Co-culture experiments were carried out as described previously [30,33,34]. Culture volumes of 100 µL per well in a 96-well plate were used, with the ratio of antigen cells to PBMCs kept at 1 : 100.…”