Vankayalapati, Ramakrishna, Ph.D.

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Research Interest:

  • NK cells and T regulatory cells in M. tuberculosis infection.

Current Projects:

  • Role of NK cells in vaccine induced protective immune responses.
  • To study the role regulatory T cells in human M. tuberculosis infection.

Identify immunologic markers of persons at highest risk of progression of latent tuberculosis infection to tuberculosis

Lay Summary:

The immune response to any infectious agent, including M. tuberculosis, is composed of an innate immune response and an adaptive immune response. The innate response is a form of natural immunity in which the immune cells have never previously encountered the pathogen, but can nevertheless eliminate it. Innate immunity explains why some persons are naturally more resistant to certain viral or bacterial infections. In contrast, the adaptive immune response depends on the immune system’s prior contact with a pathogen or antigens (immunogenic components) of that pathogen. For example, when someone receives a vaccine against hepatitis B, this primes the immune response so that when the person is exposed to hepatitis B, a strong adaptive immune response prevents infection.

Previous studies of the immune response to M. tuberculosis by tuberculosis patients and healthy tuberculin reactors have focused on the role of T-lymphocytes, a key component of the adaptive immune response. The innate immune response, mediated primarily by lymphocytes called natural killer (NK) cells, has not been studied because it is difficult to isolate these cells and maintain them in culture. Nevertheless, there is compelling evidence that the innate immunity is important in the response to tuberculosis. Many persons who have worked with tuberculosis patients for extensive periods never develop a positive tuberculin skin test, indicating that their T-cells do not recognize M. tuberculosis, and that the innate immune response clears the infection before the adaptive immune response develops. Second, there are significant differences in susceptibility of different ethnic groups to tuberculosis infection, African-Americans being three times more likely to become infected than Whites. This suggests that genetic differences result in significant differences in the innate immune response.

Selected Papers and Abstracts:

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