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The correlation between delayed hypersensitivity, lymphocyte activation and protective immunity in experimental
Parasite Immunology
|January 1, 1987
Summary
Delayed-type hypersensitivity (DTH) in mice correlates with resistance to Leishmania infections. Specific DTH responses are linked to resistance against Leishmania major and Leishmania mexicana, influencing lesion development and outcome.
Area of Science:
- Immunology
- Parasitology
- Infectious Diseases
Background:
- Leishmania major and Leishmania mexicana cause distinct disease outcomes in mice.
- Susceptibility and resistance to Leishmania species vary between mouse strains (BALB/c and CBA/Ca).
- Delayed-type hypersensitivity (DTH) is a key immune response in parasitic infections.
Purpose of the Study:
- To investigate the relationship between DTH and lesion development in mice infected with Leishmania major and Leishmania mexicana.
- To assess the role of homologous and heterologous antigens in eliciting DTH responses.
- To determine if DTH responses predict resistance or susceptibility to Leishmania infection.
Main Methods:
- Infection of BALB/c and CBA/Ca mice with Leishmania major and Leishmania mexicana.
- Monitoring of lesion growth and development.
- Measurement of DTH responses to homologous and heterologous soluble antigens at 24 and 48 hours post-challenge.
- Assessment of skin test site infiltration, including basophils.
- Induction of resistance using pre-irradiation (600 rad) followed by infection.
Main Results:
- CBA/Ca mice are resistant to L. major but susceptible to L. mexicana; BALB/c mice are susceptible to both.
- Resistance to Leishmania infection correlated with a 48-hour DTH response.
- Non-healing lesions were associated with negative DTH or early-subsided DTH (peaking at 24h, reduced by 48h), often with basophilic infiltration.
- Pre-irradiation induced resistance and a 48-hour DTH response.
- L. mexicana antigen elicited a stronger DTH response than homologous antigen in L. major-infected CBA/Ca mice, correlating with cross-immunity.
Conclusions:
- DTH response kinetics and magnitude are critical determinants of Leishmania lesion outcome.
- A robust, sustained DTH response (peaking at 48h) is associated with resistance.
- Early or absent DTH responses are linked to non-healing lesions.
- Cross-reactivity of DTH responses can indicate cross-immunity between Leishmania species.