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Increased natural killer cell activity in experimental American trypanosomiasis
Journal of Immunology (Baltimore, Md. : 1950)
|September 1, 1981
Summary
Natural killer (NK) cell activity increases early during experimental American Trypanosomiasis in mice, peaking within two days. However, this augmented NK cell response does not appear to directly protect the host against Trypanosoma cruzi infection.
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Background:
- Experimental American Trypanosomiasis, caused by Trypanosoma cruzi, involves complex host-immune responses.
- Natural killer (NK) cells are crucial innate immune cells with cytotoxic functions against various targets.
Purpose of the Study:
- To investigate the kinetics and characteristics of NK cell activity during experimental American Trypanosomiasis in mice.
- To determine the role of NK cells in host protection against Trypanosoma cruzi infection.
Main Methods:
- Induction of experimental American Trypanosomiasis in susceptible (C3H/He, C57BL/6) and resistant (beige mutant) mice.
- Measurement of natural killer (NK) cell cytotoxicity against YAC target cells using peritoneal cavity cells (PEC) and spleen cells (SC) at various time points post-infection.
- Characterization of the effector NK cell population through antibody-mediated depletion and cell separation techniques.
- Administration of heat-killed blood-form trypomastigotes (BFT) to assess NK cell activity modulation.
Main Results:
- Increased NK cell activity was detected as early as 1 day post-infection in susceptible mice, peaking at day 2.
- The effector cells exhibited characteristics consistent with NK cells, including sensitivity to anti-NK 1.2 serum and non-adherence to plastic.
- Beige mutant mice showed a delayed and significantly lower NK cell response to infection.
- Injection of heat-killed trypomastigotes also augmented NK activity.
- Augmented NK activity was observed in both resistant and susceptible strains, but the resistance phenotype in beige mutants with lower NK response suggests NK cells do not play a direct protective role.
Conclusions:
- Natural killer (NK) cell activity is rapidly induced during experimental American Trypanosomiasis in mice.
- The early NK cell response shares characteristics with NK cells found in normal mice.
- Despite early augmentation, NK cells do not appear to be directly involved in host protection against Trypanosoma cruzi infection.