Abstract
It has been stated that in the malnutrition state, the immunological competencies such as tuberclin reactivity, lymphoblastformation or antibody production are impaired. This incompetency has been considered closely related to the lowered resistance against a variety of infections in malnutrition state. On the other hand, malnutrition is sometimes considered to suppress the infection despite of the lowered state of the immunological markers such as cell mediated immunity or antibody production. The analysis of lowered immunological surveillance system has not been well analysed systematically.
We consider that it is urgent to analyse the change of various immunological systems in malnutrition state in order to control the lowered resistance against infection in malnutrition.
It is considered that, the immunological surveillance is composed of the complement system, the cell mediated system and immunoglobulin system in mammalia.
Search for the relation of the cellular immunity system and the complement system has been done employing well nourished and protein depleted rats. First, it was found that the cell mediated system measured by tuberclin reactivity of rats sensitized with heat killed tubercle bacilli was depressed by feeding with 0.5% protein diet for 8 weeks, while, the complement level was maintained. When these two groups of rats were infected with Staphylococcus aureus, both groups of rats showed elevation of complement level after Stapylococcus aureus infection, while in malnutrition rats, the tuberclin reaction remained negative but well nourished rats, tuberclin reaction positive in the reactivity.
It is possible to explain that the complement system is elevated to compensate the depressed cell-mediated system to keep the immunological surveillance system against the invading agents in protein depleted hosts as well as in aged or tumor bearing hosts.
