Lactational Vitamin E Protects Against the Histotoxic Effects of Systemically Administered Vanadium in Neonatal Rats.

The work investigated the protective role of lactational vitamin E administration on vanadium-induced histotoxicity. Three groups of Wistar rats, with each group comprising of two dams and their pups, were used in this study. Group I pups were administered intraperitoneal injection of sterile water at volumes corresponding to the dose rate of the vanadium (sodium metavanadate) treated group from postnatal day (PND) 1-14 while those in Group II were administered intraperitoneal injection of 3mg/kg vanadium from PND 1-14. Group III pups were administered intraperitoneal injection of 3mg/kg vanadium while the dam received oral vitamin E (500 mg) concurrently every 72 hours. The results showed that group II pups exhibited histopathological changes which included seminiferous tubule disruption of the testes characterised by vacuolar degeneration and coagulative necrosis of spermatogonia and Sertoli cells with reduction in mitosis, and areas of interstitial thickening with fibroblast proliferation. In addition, the lungs showed disruption of the bronchiolar wall and denudation of the bronchiolar respiratory epithelium while the liver showed hydropic degeneration and coagulative necrosis of the centrilobular hepatocytes. These histotoxic changes were ameliorated in the vanadium + vitamin E group. We conclude that lactational vitamin E protects against the histotoxic effects of vanadium and could be a consideration for supplementation in the occupationally and environmentally exposed neonates. However, caution should be taken in vitamin E supplementation because there is still equivocal evidence surrounding its benefits as a supplement at the moment.

Immunogenicity and antigenic properties of Pf332-C231, a fragment of a non-repeat region of the Plasmodium falciparum antigen Pf332.

Antigen Pf332, a megadalton protein has been shown to be associated with the membrane of infected erythrocytes. Detailed functional studies on the antigen have remained hampered by the cross-reactive nature of antibodies generated to Pf332. Pf332-C231, identified in the C-terminal region of Pf332 was cloned and antibodies against the C231 fragment were shown to react with intact Pf332 antigen by both immunofluorescence and immunoblotting analyses. Antibodies to C231 inhibited in vitro Plasmodium falciparum growth efficiently. In addition, human sera from malaria-exposed individuals reacted with recombinant C231. We show that Pf332-C231 represents a functional domain and is expected to facilitate further studies on Pf332 as a potential target for protective immune responses and the function of the antigen.

Cytokine Profiles and Antibody Responses to Plasmodium Falciparum Malaria Infection in Individuals Living in Ibadan; Southwest Nigeria

Background: The ability of the host immune system to efficiently clear Plasmodium falciparum parasites during a malaria infection depends on the type of immune response mounted by the host. Study design: In a cross-sectional study; we investigated the cellular-and antibody responses in individuals with P. falciparum infection; in an attempt to identify immunological signs indicative of the development of natural immunity against malaria in Ibadan; Nigeria. Levels of IL-10; IL-12(p70); IFN-a; and IgM; IgG and IgG1-4 subclasses in the serum of 36 symptomatic children with microscopically confirmed malaria parasitaemia and 54 asymptomatic controls were analysed by ELISA. Results: IFN-a and IL-10 were significantly higher in the symptomatic children (p=0.009; p=0.025 respectively) than in the asymptomatic controls but no differences were seen for IL-12(p70). Estimated higher ratios of IFN-a/IL-10 and IFN-a/IL-12 were also observed in the symptomatic children while the asymptomatic controls had higher IL-12/IL-10 ratio. The mean concentration levels of anti-P. falciparum IgG1; IgG2; IgG3 antibodies were statistically significantly higher in the individuals 5 years of age than 5 years while anti-P. falciparum IgG3 antibodies were notably low in 5 years category. Children 5 years had higher IgM antibodies than IgG and the expression of IgG subclasses increased with age. Conclusion: Taken together; malaria infection is on a delicate balance of pro- and anti-inflammatory cytokines. The higher levels of IFN-a seen in the symptomatic children (6months) may be instrumental in immune-protection against malaria by limiting parasite replication. The observed variations in immunoglobulin subclass levels were age- dependent and exposure-related

Fc gamma receptor IIa (CD32) polymorphism and antibody responses to asexual blood-stage antigens of Plasmodium falciparum malaria in Sudanese patients.

In a prospective clinical study in New Halfa Teaching Hospital, the possible association between FcgammaRIIa-R/H131 polymorphism and anti-malarial antibody responses with clinical outcome of Plasmodium falciparum malaria among Sudanese patients was investigated. A total of 256 individuals were consecutively enrolled, comprising 115 patients with severe malaria, 85 with mild malaria and 56 malaria-free controls. Genotyping of FcgammaRIIa-R/H131 dimorphism was performed using gene-specific polymerase chain reaction (PCR) amplification with allele-specific restriction enzyme digestion of the PCR product. The antibody responses to asexual blood-stage antigens were assessed by an enzyme-linked immunosorbent assay. The frequency of the FcgammaRIIa-R/R131 genotype was significantly higher in those with severe malaria when compared with patients with mild malaria, while the FcgammaRIIa-H/H131 genotype showed a significant association with mild malaria. A reduced risk of severe malaria with IgG3 antibodies in combination with the H/H131 genotype was observed. Furthermore, low levels of IgG2 antibodies reactive with the Pf332-C231 antigen were also associated with lower risk of severe malaria in individuals carrying the H131 allele. The levels of IgG1 and IgG3 antibodies were statistically significantly higher in the mild malaria patients when compared with the severe malaria patients. Taken together, our study revealed that the FcgammaRIIa-R/R131 genotype is associated with the development of severe malaria, while the H/H131 genotype is more likely to be associated with mild malaria. Our results also revealed that the natural acquisition of immunity against clinical malaria appeared to be more associated with IgG1 and IgG3 antibodies, signifying their roles in parasite-neutralizing immune mechanisms.