Stiffel C

A Major Role of the Macrophage in Quantitative Genetic Regulation of Immunoresponsiveness and Antiinfectious Immunity

Publisher Summary It is clear today that the immune system is constituted by a coordinated network of perfectly integrated and interacting cells and molecules subject to strict cooperation to ensure the highest possible efficiency in antiinfectious immunity. A simplified scheme of the immune system in higher vertebrates is represented in this chapter. The enzyme equipment of macrophage phagosomes endows these cells with bactericidal or bacteriostatic activity on ingested microorganisms, therefore, constituting the first important mechanism in antiinfectious defense. The metabolic activity of macrophages on engulfed antigens also regulates the specific response of T and B lymphocytes through a complex process of antigen handling and antigen presentation, establishing a sort of symbiotic relationship between lymphocytes and macrophages. There are two essential components in the immune response: one is specific and the other nonspecific. The specific response involves the stereospecific selective recognition. The nonspecific aspect of the immune response includes the handling of the phagocytized antigen and the rate at which the process of multiplication and differentiation of small lymphocytes takes place. The protective effect of specific vaccination is essentially based on immunological memory. The antibody molecules, according to their isotypes, play specialized defensive roles against various types of invading microorganisms, particularly in collaboration with the complement system, inducing bactericidal or opsonizing effects.

Genetic Regulation of High and Low Immunoresponsiveness

The immune deficiencies (ID) may be classified into two broad categories: primitive ID and ID produced by environmental causes (nutrition, infection, neoplasia, ionizing radiation, etc.). The primitive ID are due essentially to genetic factors acting at the level of the immune system.

Study of the mechanism of Corynebacterium parvum antitumour activity: Protective effect in mice submitted to sublethal doses of irradiation

SummaryThe antitumour activity of C. parvum against two different tumours, a lymphosarcoma grafted in XVII mice and a mammary carcinoma grafted in C3H mice, was a radiosensitive phenomenon. A dose of X-rays as low as 100 rads was sufficient to abrogate the C. parvum-induced protection. The duration of this inhibition increased with augmentation of the X-ray dose. The stimulation of macrophage-phagocytic activity induced by C. parvum was not inhibited by a dose of 500 rads. A chronological parallelism has been demonstrated in the recovery of the C. parvum antitumour effect and the restoration of antibody responsiveness after the suppression of these two activities by 500 rads of X-rays in the case of the C3H mice grafted with mammary carcinoma cells. No such concomitant recovery has been observed in XVII mice. In these mice, the recovery of C. parvum antitumour activity took place before the restoration of antibody responsiveness.

Activité antitumorale de différentes doses de corynebacterium parvumen fonction de l'age de la souris

Summary The anti-tumour activity of Corynebacterium parvum against two different tumours, a mammary carcinoma grafted in C3H mice and a lymphosarcoma grafted in XVII mice, was lower in young and old mice, than in adult ones. In young mice (25 days) of both lines, low doses of C. parvum were more efficient than higher doses. In 12-month old XVII mice a higher survival rate was obtained by increasing the dose of C. parvum administered, whereas in old C3H mice, this phenomenon was not observed. Sublethal doses of X-irradiation abrogated the C. parvum -induced protection. Restoration of the protective effect occurred faster in 3-month old mice than in 8-month old mice. This restoration appeared earlier in XVII mice than in C3H mice.