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Protective effect of Nocardia opaca lysozyme digest in experimental murine Candida albicans infections
1Department of Immunology, Institute of Microbiology, Sofia, Bulgaria. nina@microbio.bas.bg
Abstract:
Candida albicans, as an opportunistic pathogen, causes therapeutic problems in immunocompetent individuals and frequently it initiates severe infections in immunocompromised hosts. The application of a lysozyme digest preparation from the cell walls of Nocardia opaca (Nocardia lysozyme digest; NLD), recently classified as Rhodococcus opacus, has a protective effect in intravenous (i.v.) C. albicans infections in inbred ICR mice which have normal complement production. It also significantly reduces i.v. and intraperitoneal (i.p.) infections in DBA/2 mice which are deficient in C5 complement component. A significant decrease in C. albicans recovery from kidneys was found in NLD-treated DBA/2 animals. The preparation enhanced delayed type hypersensitivity to the yeast cells in both mouse strains. C. albicans-induced popliteal lymph node reactions were increased in ICR mice. In addition, mouse splenocytes that had been inhibited in their proliferative response to phytohaemagglutinin had this response restored after exposure to the preparation. NLD decreased the sensitivity of both mouse strains to a second challenge with the pathogen. The preparation restored the impaired host response to C. albicans infection in ICR mice treated with cobra venom and cyclophosphamide.
Insights
Nocardia lysozyme digest (NLD) protects against Candida albicans infections by enhancing immune responses. This preparation shows protective effects in various mouse models, including those with compromised immune systems.
Area of Science:
- Immunology
- Microbiology
- Pathogen Research
Background:
- Candida albicans is an opportunistic pathogen causing infections in both immunocompetent and immunocompromised individuals.
- Therapeutic challenges exist for managing C. albicans infections, particularly in vulnerable populations.
Purpose of the Study:
- To evaluate the protective effects of Nocardia lysozyme digest (NLD) against C. albicans infections in mice.
- To investigate NLD's impact on host immune responses and its efficacy in different complement-proficient and deficient models.
Main Methods:
- Administration of NLD to inbred ICR (complement-normal) and DBA/2 (C5-deficient) mice infected with C. albicans.
- Assessment of C. albicans burden, delayed-type hypersensitivity, lymph node reactions, splenocyte proliferation, and host resistance to secondary challenge.
- Evaluation of NLD's efficacy in immunocompromised mouse models (cobra venom and cyclophosphamide treated).
Main Results:
- NLD demonstrated protective effects against intravenous C. albicans infections in both mouse strains.
- Significant reduction in C. albicans recovery from kidneys was observed in NLD-treated DBA/2 mice.
- NLD enhanced delayed-type hypersensitivity, boosted lymph node reactions, restored splenocyte proliferation, and decreased susceptibility to secondary infections.
- The preparation restored impaired host responses in immunosuppressed mice.
Conclusions:
- Nocardia lysozyme digest (NLD) exhibits significant immunomodulatory and protective properties against Candida albicans infections.
- NLD's efficacy extends to various host conditions, including complement deficiency and induced immunosuppression, highlighting its therapeutic potential.