Interferon-? responses to Plasmodium falciparum vaccine candidate antigens decrease in the absence of malaria transmission.

ABSTRACT:

Background

Malaria elimination campaigns are planned or active in many countries. The effects of malaria elimination on immune responses such as antigen-specific IFN- ? responses are not well characterized.

Methods

IFN- ? responses to the P. falciparum antigens circumsporozoite protein, liver stage antigen-1, thrombospondin-related adhesive protein, apical membrane antigen-1, MB2, and merozoite surface protein-1 were tested by ELISA in 243 individuals in highland Kenya in April 2008, October 2008, and April 2009, after a one-year period of interrupted malaria transmission from April 2007 to March 2008.

Results

While one individual (0.4%) tested positive for P. falciparum by PCR inOctober 2008 and another two (0.9%) tested positive in April 2009, no clinical malaria cases were detected during weekly visits. Levels of IFN-? to all antigens decreased significantly from April 2008 to April 2009 (all P < 0.001).

Discussion

Naturally acquired IFN- ? responses to P. falciparum antigensare short-lived in the absence of repeated P. falciparum infection. Even short periods of malaria interruption may significantly decrease IFN-? responses to P. falciparum antigens.

SUBMITTER: Ayieko C 

PROVIDER: S-EPMC5228499 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature