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Passive Administration of Monoclonal Antibodies Against H. capsulatum and Others Fungal Pathogens
Published on: February 14, 2011
Human lymphocyte blastogenesis induced by living and dead Histoplasma capsulatum yeasts and soluble yeast autolysate
Abstract:
Human peripheral blood mononuclear cells were cultured with either replicating yeast phase Histoplasma capsulatum, intact dead yeasts of soluble yeast phase autolysate antigen for induction of lymphocyte blastogenesis. H. capsulatum replicated to the same extent in cultures of lymphocytes from histoplasmin skin test-positive and negative cell donors, but stimulated far greater blastogenesis in the former. Dead H. capsulatum yeasts, which were more easily quantified, caused nearly as much specific blastogenesis as live yeasts. Blastogenesis was induced by as few as 1 dead yeast per 10,000 lymphocytes, indicating the antigenic potency of Histoplasma yeasts. Specific blastogenesis was also caused by soluble yeast autolysate. Thus, replicating H. capsulatum yeasts, dead yeasts and autolytically released soluble yeast phase antigen each stimulated specific blastogenesis of lymphocytes from persons sensitized to H. capsulatum in vivo.
Insights
Histoplasma capsulatum yeasts, whether live, dead, or as soluble antigen, effectively stimulate lymphocyte blastogenesis in sensitized individuals. This highlights the potent antigenicity of Histoplasma yeasts for immune response.
Area of Science:
- Immunology
- Mycology
- Infectious Diseases
Background:
- Histoplasma capsulatum is a fungal pathogen causing histoplasmosis.
- Immune responses, particularly lymphocyte activation, are crucial for controlling fungal infections.
- Understanding the specific antigens that elicit cellular immunity is vital for diagnostics and therapeutics.
Purpose of the Study:
- To investigate the ability of different forms of Histoplasma capsulatum to induce lymphocyte blastogenesis.
- To compare the immunogenicity of replicating yeasts, dead yeasts, and soluble yeast phase antigen.
- To determine the sensitivity of lymphocyte response to Histoplasma antigens.
Main Methods:
- Peripheral blood mononuclear cells from healthy donors (histoplasmin skin test-positive and negative) were cultured.
- Cultures were stimulated with live yeast phase Histoplasma capsulatum, intact dead yeasts, or soluble yeast phase autolysate antigen.
- Lymphocyte blastogenesis was measured as an indicator of cellular immune response.
Main Results:
- Both live and dead Histoplasma capsulatum yeasts induced significant lymphocyte blastogenesis.
- Dead yeasts were nearly as effective as live yeasts in stimulating blastogenesis and were easier to quantify.
- Soluble yeast phase autolysate antigen also elicited a specific blastogenic response, even at low concentrations (1 dead yeast per 10,000 lymphocytes).
Conclusions:
- Replicating, dead, and soluble antigens of Histoplasma capsulatum all effectively stimulate lymphocytes from sensitized individuals.
- Dead yeasts and soluble antigens represent potent and practical tools for assessing cellular immunity to Histoplasma.
- These findings underscore the significant antigenic potency of Histoplasma yeasts in vivo.
