Acquired antibody responses against merozoite surface protein-119 antigen during Plasmodium falciparum and P.vivax infections in South Indian city of Mangaluru

Abstract

Merozoite surface protein-1 (MSP-1) of malaria parasites has been extensively studied as a malaria vaccine candidate and the antibody response to this protein is an important indicator of protective immunity to malaria. Mangaluru city and its surrounding areas in southwestern India are endemic to malaria with Plasmodium vivax being the most widespread and prevalent species although P. falciparum also frequently infects. However, no information is available on the level of protective immunity in this population. In this regard, a prospective hospital-based study was performed in malarial patients to assess antibody responses against the 19-kDa C-terminal portion of P. vivax and P. falciparum MSP-1 (MSP-1 19 ). Serum samples from 51 healthy endemic controls and 267 infected individuals were collected and anti-MSP-1 19 antibody levels were analyzed by ELISA. The possible association between the antibody responses and morbidity parameters such as malarial anemia and thrombocytopenia was investigated. Among the 267 infected cases, 144 had P. vivax and 123 had P. falciparum infections. Significant levels of anti-MSP-1 19 antibody were observed both in P. vivax (123/144; 85.4%) and P . falciparum (108/123; 87.9%) infected individuals. In both type of infections, the major antibody isotypes were IgG1 and IgG3. The IgG levels were found to be increased in patients with severe anemia and thrombocytopenia. The antibody levels were also higher in infected individuals who had several previous infections, although antibodies produced during previous infections were short lived. The predominance of cytophilic anti-MSP-1 19 IgG1 and IgG3 antibodies suggests the possibility of a dual role of Pv MSP-1 19 and Pf MSP-1 19 during malarial immunity and pathogenesis.

Plasmodium vivax MSP1-42 kD Variant Proteins Detected Naturally Induced IgG Antibodies in Patients Regardless of the Infecting Parasite Phenotype in Mesoamerica

“…The heterogeneity in the IgG OD values for PvMSP1 42 proteins was similar to that observed for the NBSA, which was irrespective of the parasite haplotype. Heterogeneity in IgG responses against PvMSP1 fragments and other molecules has been observed in previous studies [ 27 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

Malarial Antibody Detection with an Engineered Yeast Agglutination Assay

“…Our selection of P. falciparum as an initial target was motivated by it being the most common malarial species in Palawan, Philippines (where several of us have been involved in malaria diagnosis and surveillance projects); a previous study found 74% of malaria infections arising in the region containing Palawan to arise from P. falciparum , while 18% arose from P. vivax . A comparison of the P. falciparum and P. vivax -specific antigens (Pf-MSP-1 19 and Pv-MSP-1 19 ) has demonstrated the ability to distinguish antibodies caused by infection with the two species, − suggesting that our assay could be extended to create two variants of Cell 1, one expressing each of the species-specific antigens; we plan to pursue this in future work.…”

Identification and serological responses to a novel Plasmodium vivax merozoite surface protein 1 (PvMSP-1) derived synthetic peptide: a putative biomarker for malaria exposure

“…It is important to note that while the Pv MSP-1 19 subunit is widely recognized and validated as one of the highly immunogenic parts of the protein ( Longley et al, 2020 ; Punnath et al, 2021 ), we have discovered through the SPOT-synthesis technique that other most reactive peptides do not align with this region. This outcome is likely due to the conformation-dependent nature of immunogenicity in this particular segment, as many studies use the recombinant expression of this subunit ( Cunha, Rodrigues & Soares, 2001 ; Bueno et al., 2008 ; Rocha et al, 2017 ).…”

“…Malarial infection elicits high antibody titers, mostly against the parasite’s blood stage, and those molecules persist even after treatment ( Braga, Fontes & Krettli, 1998 ; Morais et al, 2005 ; Costa et al, 2020 ). Individuals living in endemic areas for P. vivax swiftly develop considerable titers of antibodies towards specific parasite antigens ( Bueno et al, 2011 ; Fantin et al, 2021 ; França et al, 2021 ; Punnath et al, 2021 ; Tayipto et al, 2022 ). The identification of antibodies that target P. vivax antigens holds utility in delineating vivax malaria transmission regions, pinpointing asymptomatic reservoirs, predicting outbreaks, and facilitating the effective deployment of control measures, including prompt treatment ( Greenwood et al, 2008 ; Kim et al, 2014 ; Longley et al, 2017 ; O’Flaherty, Roe & Fowkes, 2022 ).…”