Related Experiment Videos
Effect of single carcinogenic dose of dimethylnitrosamine on antibody responses in the rat
Abstract:
The immunodepressive effect of a single, carcinogenic dose of dimethylnitrosamine was tested in a potent model of renal cancer induction using two antigens which differ in their cellular processing. Responsiveness to sheep red blood cells (SRBC), an antigen requiring the collaboration of both thymus-dependent (T) and thymus-independent (B) lymphocytes was determined by a plaque-forming assay; antibody production to Brucella abortus antigen, a thymus-independent antigen was measured in an agglutination test. The results suggested that DMN exerted little or no effect on B lymphocytes in the anti-SRBC antibody response. This effect commenced immediately following the carcinogenic insult from 24 h, with a degree of depression for the first 10 days equivalent to antilymphocyte globulin in terms of numbers of anti-SRBC antibody-forming cells. From 2 weeks there was gradual recovery with full restoration of normal responsiveness at 8 weeks. During the ensuing period of emergence of neoplastic foci in the kidney, and with the progression of such foci to tumors of macroscopic dimensions, there was no accompanying depression of antibody response. The differential effect was discussed in terms of selectivity of action, and lymphocyte subsets.
Insights
Dimethylnitrosamine (DMN) exposure temporarily depresses immune response to thymus-dependent antigens, affecting T and B lymphocytes. Kidney cancer development did not correlate with sustained immune suppression.
Area of Science:
- Immunology
- Toxicology
- Oncology
Background:
- Dimethylnitrosamine (DMN) is a potent carcinogen.
- The impact of DMN on the immune system, particularly in renal cancer induction, requires further elucidation.
- Understanding immune response modulation is crucial for cancer research.
Purpose of the Study:
- To investigate the immunodepressive effects of a single carcinogenic dose of DMN.
- To assess the impact of DMN on T-cell and B-cell dependent immune responses.
- To correlate immune response changes with renal cancer development in a rodent model.
Main Methods:
- Utilized a rodent model for potent renal cancer induction with DMN.
- Assessed immune response to sheep red blood cells (SRBC), a T-cell and B-cell dependent antigen, via plaque-forming assay.
- Measured antibody production to Brucella abortus antigen, a T-cell independent antigen, using an agglutination test.
Main Results:
- DMN induced a significant, temporary depression in antibody-forming cells against SRBC, comparable to antilymphocyte globulin.
- This immunosuppression began within 24 hours and lasted for approximately 10 days, with gradual recovery over 8 weeks.
- No significant effect on antibody production to the T-cell independent Brucella abortus antigen was observed.
- Immune response remained normal during the development and progression of kidney tumors.
Conclusions:
- DMN exhibits a selective immunodepressive effect, primarily impacting thymus-dependent antibody responses.
- The observed immunosuppression is transient and does not persist with tumor progression.
- Findings suggest DMN's impact on lymphocyte subsets may be specific, warranting further investigation into mechanisms.