Self And The Phenomenon Of Life: A Biologist Examines Life From Molecules To Humanity

The Animal Self: Molecular Recognition 125

“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity

of self) on the cell surface. Natural killer (NK) cells consider these
MHC-deficient cells as non-self and destroy them.^12 People with deficient
NK cell activity have been associated with increased cancer risk, such as
prostate cancer and melanoma. Experiments in mice also show that NK
cells protect the host against certain chemically induced tumors.^13

Notes and References

1. Gibson T, Medawar PB. (1943) The fate of skin homografts in man. J Anatomy
   77: 299–310.


2. Landsteiner K. (1901) Uber agglutinationserscheinungen normalen men-
   schlichen blutes. Wiener Klin Wschr 14: 1132–1134.


3. Although organ transplantation and blood transfusion both involve immu-
   nity and self-recognition, there are differences between the two. First, in
   transplantation the immune reaction is cell mediated whereas in transfusion
   it is antibody mediated. Second, organ transplantation has a more stringent
   self-recognition than transfusion, as the former recognizes differences from
   individual to individual, whereas the latter, between groups of individuals.
   Third, in organ transplants the host encounters the foreign molecules for the
   first time, and therefore a lag period is needed to elicit a full immune re-
   sponse; in blood transfusion the response is immediate because the antibodies
   against the antigens are already in the blood, as the recipient has earlier been
   exposed to the same antigens found in food and common microbes. Fourth, in
   transfusion of whole blood, only the donor red cells are of importance, as they
   are the major cellular elements in the blood. Plasma from the donor is greatly
   diluted and does not play a significant role in the overall transfusion reaction.


4. In China, powdered smallpox scabs were blown up the noses of the healthy.
   The patients would then develop a mild case of the disease and from
   then on were immune to it. See: Temple R. (1986) The Genius of China:
   3000 Years of Science, Discoveries and Inventions. Simon and Schuster,
   New York, pp. 135–137.


5. Although innate immunity is adaptive in the evolutionary sense, the term
   “adaptive immunity” is reserved for the acquired type of immunity.


6. Zasloff M. (2002) Antimicrobial peptides of multicellular organisms.
   Nature 415: 389–395; Giuliani A, Giovanna P, Nicoletto SF. (2007)