Schistosoma mansoni Infection Can Jeopardize the Duration of Protective Levels of Antibody Responses to Immunizations against Hepatitis B and Tetanus Toxoid

Abstract

BackgroundSchistosomiasis is a disease of major public health importance in sub-Saharan Africa. Immunoregulation begins early in schistosome infection and is characterized by hyporesponsiveness to parasite and bystander antigens, suggesting that a schistosome infection at the time of immunization could negatively impact the induction of protective vaccine responses. This study examined whether having a Schistosoma mansoni infection at the time of immunization with hepatitis B and tetanus toxoid (TT) vaccines impacts an individual’s ability to achieve and maintain protective antibody levels against hepatitis B surface antigen or TT.MethodsAdults were recruited from Kisumu Polytechnic College in Western Kenya. At enrollment, participants were screened for schistosomiasis and soil transmitted helminths (STHs) and assigned to groups based on helminth status. The vaccines were then administered and helminth infections treated a week after the first hepatitis B boost. Over an 8 month period, 3 blood specimens were obtained for the evaluation of humoral and cytokine responses to the vaccine antigens and for immunophenotyping.Results146 individuals were available for final analysis and 26% were S. mansoni positive (Sm+). Schistosomiasis did not impede the generation of initial minimum protective antibody levels to either hepatitis B or TT vaccines. However, median hepatitis B surface antibody levels were significantly lower in the Sm+ group after the first boost and remained lower, but not significantly lower, following praziquantel (PZQ) treatment and final boost. In addition, 8 months following TT boost and 7 months following PZQ treatment, Sm+ individuals were more likely to have anti-TT antibody levels fall below levels considered optimal for long term protection. IL-5 levels in response to in vitro TT stimulation of whole blood were significantly higher in the Sm+ group at the 8 month time period as well.ConclusionsIndividuals with schistosomiasis at the start the immunizations were capable of responding appropriately to the vaccines as measured by antibody responses. However, they may be at risk of a more rapid decline in antibody levels over time, suggesting that treating schistosome infections with praziquantel before immunizations could be beneficial. The timing of the treatment as well as its full impact on the maintenance of antibodies against vaccine antigens remains to be elucidated.

An investigation into the role of chronic Schistosoma mansoni infection on Human Papillomavirus (HPV) vaccine induced protective responses

“…The study provided an indication that the study subjects with chronic schistosomiasis were capable of responding to the vaccines and produced HPV specific IgG antibodies, however, after the 6 th week a decrease in IgG levels was observed. This reduced humoral response has also been observed in helminth infected subjects administered with a number of vaccines [22,[40][41][42].…”

“…Schistosomiasis, has been estimated to affect more than 250 million people with majority of cases occurring in Sub-Saharan Africa [18]. Several studies have shown that parasitic infections, especially schistosomiasis, impair long-term responses of certain vaccines such as BCG [19], TB [20], hepatitis B [21] and tetanus toxoid [22] that require a predominant Th1 response to be effective. During a chronic helminth infection, there is a characteristic induction of a Th2 response which down regulates Th1 responses.…”

“…These immune response is essential for host's survival against the toxic effects of the Schistosoma egg antigens [23][24][25]. [20,22].…”

Effect of four rounds of annual school‐wide mass praziquantel treatment for schistosoma mansoni control on schistosome‐specific immune responses

“…1.75 mL of the heparinized blood was used to set up whole‐blood cultures for evaluation of in vitro production of cytokines (IL‐5, IL‐10, IL‐13, IFN‐γ) as previously described . Briefly, blood was diluted 1:5 in culture media (RPMI 1640, 1% L‐glutamine, 1% Penicillin‐streptomycin).…”

Lymph node fibrosis: a structural barrier to unleashing effective vaccine immunity

“…Reduced responses to vaccinations for tetanus toxoid (23), cholera (24), and BCG (25) have been associated with helminth coinfection, and children with malaria have been shown to mount weaker antibody responses to tetanus toxoid, Haemophilus influenzae, meningococcal polysaccharide, and Salmonella typhi vaccination (26) than uninfected children. While some parasitic infections do not affect the initial generation or levels of protective antibody, parasitic infections clearly affect the durability of these immune responses, as reported for HBV or tetanus toxoid vaccines in chronic schistosomiasis (27). Several mechanisms have been proposed for the antagonizing effects that coinfection has on vaccine durability.…”