Tolerance to sheep red cells: breakage with thymocytes and horse red cells.

This study examines how mice, initially made tolerant to sheep red blood cells, respond differently to direct exposure to normal thymocytes and horse red blood cells, resulting in different antibody reactions. The findings suggest that certain immune cells may exist in a tolerant host but are not activated by the specific antigen.

Objective

The main goal of this research is to understand the immune response of mice that have been rendered tolerant to sheep red blood cells when exposed to different antigens (thymocytes and horse red blood cells). The study aims to determine if there are nonactivated but not tolerant immune cells present in these tolerant organisms.

Methodology

• The researchers started the experiment by inducing tolerance in mice to sheep red blood cells. This was established to create a baseline immune response or lack thereof.
• After the tolerance was established, the mice were exposed to normal thymocytes. Here, the researchers were interested in observing if the mice would subsequently produce antibodies following the introduction of these cells.
• Next, the mice were subjected to horse red blood cells and again observed for any signs of antibody production in response to these cells.

Results

• The results showed that mice did not generate an antibody response when exposed to the normal thymocytes. This indicated that their previously induced tolerance to sheep red blood cells extended to these types of cells.
• On the contrary, when exposed to horse red blood cells, the mice generated a significant amount of noncross-reacting antibody to sheep red blood cells. This was an unexpected response showing the breakage of tolerance, and it differed distinctly from the response to thymocytes.

Conclusion

• The different reactions observed in the mice suggested the presence of immune cells (precursor B cells) which are not activated by their specific antigen yet are also not tolerant. This could possibly explain why these mice displayed a distinct response to the two different types of cells – thymocytes and horse red blood cells.
• The B cells may have been nonreactive due to previous tolerance to sheep red blood cells but were non-tolerized and thus able to respond to the horse red blood cells.