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Cell-mediated and humoral immune response to tetanus vaccinations in onchocerciasis patients
1Department of Helminthology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, FRG.
Abstract:
In order to assess the possible suppression of immune responses to non-specific antigens in patients with generalized onchocerciasis, a vaccination study was conducted among the population of eight Liberian villages. Hundred and eighty-four persons infected with Onchocerca volvulus and 142 non-infected individuals were tested for delayed cutaneous hypersensitivity to tetanus antigen using the Multitest Mérieux. Prevalence of malaria and infections with intestinal nematodes with larval migration to the lung were much the same in all the villages examined. Other parasitic diseases had no significant influence. Persons aged 2-29 years with onchocerciasis had a significantly lower prevalence of positive tetanus reactions (p less than 0.05). Hundred and eighty persons showing a negative skin test were vaccinated twice with 75 i.u. tetanus toxoid and cell-mediated as well as humoral immune responses were recorded three months later. Analysis of sera collected before vaccinations indicated that 56% of the vaccinees had tetanus antibody levels of 0.01 i.u./ml or more and had, therefore, received a booster vaccination. Rates of seroconversion or booster were the same in persons with or without onchocerciasis (81% and 82% respectively). The conversion rate in the delayed cutaneous hypersensitivity test, however, was significantly lower in those infected with O. volvulus (67%) as compared to the controls (92%, p less than 0.001). These results demonstrate a diminished cell-mediated immune response to tetanus toxoid vaccinations in patients with generalized onchocerciasis. Considering the unimpaired humoral immune response, no changes in vaccination schedules are recommended.
Insights
Generalized onchocerciasis may suppress cell-mediated immunity. This study found diminished immune responses to tetanus toxoid vaccination in infected individuals, though antibody levels remained normal.
Area of Science:
- Immunology
- Tropical Medicine
- Vaccinology
Background:
- Generalized onchocerciasis is a parasitic disease affecting millions.
- Immune suppression in onchocerciasis may impact responses to other antigens.
- Assessing immune function is crucial for public health interventions.
Purpose of the Study:
- To evaluate immune responses to non-specific antigens in patients with onchocerciasis.
- To investigate the effect of onchocerciasis on cell-mediated and humoral immunity following tetanus toxoid vaccination.
Main Methods:
- A vaccination study was conducted in Liberian villages involving individuals with and without onchocerciasis.
- Delayed cutaneous hypersensitivity to tetanus antigen was assessed.
- Cell-mediated and humoral immune responses post-vaccination were measured.
Main Results:
- Individuals with onchocerciasis showed a significantly lower prevalence of positive tetanus skin reactions.
- Humoral immune responses (antibody levels) to tetanus toxoid vaccination were similar between infected and non-infected groups.
- Cell-mediated immune responses, indicated by delayed cutaneous hypersensitivity conversion, were significantly lower in onchocerciasis patients.
Conclusions:
- Generalized onchocerciasis diminishes cell-mediated immune responses to tetanus toxoid vaccination.
- Humoral immunity appears unaffected, suggesting no need to alter current vaccination schedules.
- Further research into immune modulation by onchocerciasis is warranted.