Two general types of immunity are recognized – natural immunity and acquired immunity. The word "immune" is derived from the Latin stem immuno, meaning safe, or free from. In its most general sense, the term implies a condition under which an individual is protected from disease. This does not mean, however, that one is immune to all diseases, but rather [...]
A number of tests are employed for the serodiagnosis of syphilis. Some of these are based on the complement-fixation technique; others are flocculation tests. The most important ones are known as: (1) The Wassermann test and its many modifications, (2) The Kahn test, and (3) The Kline test. 1. Wassermann Test: A complement-fixation test was proposed by Wassermann in which [...]
The mechanism of humoral immunity is accomplished after interaction of antigen with B-cells, antibody production and antigen-antibody binding. 1. Interaction of antigen with B-cells: The B-cells after production from the stem cells (Fig. 22.8) migrate to lymphoid organs. When antigen interacts and contacts the receptor, the later gets stimulated. The B-cells differentiate into antibody producing cells through three steps: activation, [...]