Suppression of Plasmodium falciparum by serum collected from a case of Plasmodium vivax infection

• Main Authors: Nagao, Yoshiro, Kimura-Sato, Masako, Porntip Chavalitshewinkoon-Petmitr, พรทิพย์ เพ็ชรมิตร, Supatra Thongrungkiat, สุพัตรา ทองรุ่งเกียรติ, Polrat Wilairatana, พลรัตน์ วิไลรัตน์, Ishida, Takafumi, Peerapan Tan-ariya, Souza, J. Brian de, Srivicha Krudsood, ศรีวิชา ครุฑสูตร, Sornchai Looareesuwan, ศรชัย หลูอารีย์สุวรรณ
• Format: Article
• Language: English
• Published: 2012
• Subjects: Antibodies, Protozoan; Antigens, Protozoan; Cross Reactions; Plasmodium falciparum; Plasmodium vivax; Open Access article
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/721
• Institution: Mahidol University

BACKGROUND: It has frequently been reported that Plasmodium vivax suppressed Plasmodium falciparum and ameliorated disease severity in patients infected with these two species simultaneously. The authors investigate the hypothesis that immunological responses stimulated by P. vivax may play a role in suppressing co-infecting P. falciparum. METHODS: Sera, taken sequentially from one of the authors (YN) during experimental infection with P. vivax, were added to in vitro cultures of P. falciparum. Cross-reactive antibodies against P. falciparum antigens, and cytokines were measured in the sera. RESULTS: Significant growth inhibitory effects upon P. falciparum cultures (maximally 68% inhibition as compared to pre-illness average) were observed in the sera collected during an acute episode. Such inhibitory effects showed a strong positive temporal correlation with cross-reactive antibodies, especially IgM against P. falciparum schizont extract and, to a lesser degree, IgM against Merozoite Surface Protein (MSP)-119. Interleukin (IL)-12 showed the highest temporal correlation with P. vivax parasitaemia and with body temperatures in the volunteer. CONCLUSION: These results suggest the involvement by cross-reactive antibodies, especially IgM, in the interplay between plasmodial species. IL-12 may be one of direct mediators of fever induction by rupturing P. vivax schizonts, at least in some subjects. Future studies, preferably of epidemiological design, to reveal the association between cross-reactive IgM and cross-plasmodial interaction, are warranted.