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Characteristics of cellular and humoral immune responses after immunization with different rabies vaccines
Abstract:
Three rabies vaccines were compared: 1. the Fermi type vaccine, a phenol-treated suspension of brain tissue from infected sheep; 2. a virus grown in sheep brain, purified from the contaminating material to 85-90% and inactivated with beta-propiolactone; 3. and the MNIIP-74 strain cultured in Japanese quail embryo cells and inactivated with beta-propiolactone. A single immunization of mice with any of the preparations resulted in about 50% inhibition of splenocyte migration after 2 days; by day 15 the inhibition was 95-98%. By day 45 the migration index returned to the initial level. Increased ability to blast transformation in splenocytes was found by day 15, reached the maximum (160 to 212% of the control level taken for 100%) by day 30, and then began to decrease. The most marked change in blast transformation was brought about by the purified cerebral vaccine, while the less marked one by the tissue culture vaccine. The titre of virus-neutralizing antibodies reached a maximum after 15-30 days, 60 days after immunization it dropped twice. The resistance of mice to intracerebral infection with the rabies virus shortly after immunization might be due to cellular protective factors, while at later intervals it correlated with the level of virus-neutralizing antibodies.
Insights
This study compared three rabies vaccines in mice. All vaccines induced strong immune responses, with cellular immunity peaking early and antibody levels later, providing protection against rabies virus.
Area of Science:
- Immunology
- Virology
- Vaccinology
Background:
- Rabies remains a significant public health concern, necessitating effective vaccine strategies.
- Understanding the immunodynamics of different rabies vaccine preparations is crucial for optimizing prophylaxis.
- Previous rabies vaccines have utilized various antigen sources and inactivation methods.
Purpose of the Study:
- To compare the immunogenicity and efficacy of three distinct rabies vaccine formulations in a murine model.
- To evaluate the cellular and humoral immune responses elicited by different vaccine types.
- To correlate immune responses with protection against rabies virus challenge.
Main Methods:
- Three rabies vaccines were tested: Fermi type (phenol-treated sheep brain), purified sheep brain virus (beta-propiolactone inactivated), and MNIIP-74 strain (quail embryo cell culture, beta-propiolactone inactivated).
- Immunogenicity was assessed by measuring splenocyte migration inhibition and blast transformation.
- Virus-neutralizing antibody titers and resistance to intracerebral rabies virus challenge were determined.
Main Results:
- All vaccines induced significant splenocyte migration inhibition (95-98% by day 15), which waned by day 45.
- Splenocyte blast transformation increased, peaking by day 30, with the purified cerebral vaccine showing the most pronounced effect.
- Virus-neutralizing antibody titers peaked at 15-30 days post-immunization and decreased by day 60.
Conclusions:
- Early post-immunization protection against rabies virus may be mediated by cellular immune factors.
- Later protection correlates with the level of virus-neutralizing antibodies.
- Different rabies vaccine preparations elicit comparable, yet distinct, patterns of cellular and humoral immune responses.