IMMUNOLOGICAL UNRESPONSIVENESS TO PROTEIN ANTIGENS IN RABBITS EXPOSED TO X IRRADIATION OR 6-MERCAPTOPURINE TREATMENT

Journal Article · Mon Jul 01 04:00:00 EDT 1963 · Immunology (England)

OSTI ID:4657594

Nachtigal, D; Feldman, M

Immune unresponsiveness to human and bovine serum albumin was induced in adult rabbits exposed to 550-r total-body irradiation. Immunogenic doses of antigen, 20 -75 mg, were found to be tolerogenic in this system. The degree of unresponsiveness was found to be a function of the time interval between x irradiation and the beginning of antigen administration. The unresponsive animals retained the circulating antigen in quantities detectable by the geldiffusion technique. These results were similar to the state of unresponsiveness induced by means of 6-mercaptopurine. Thus potentially immunogenic doses of antigen could confer tolerance in x-ray and 6-mercaptopurine treated animals. The level of tolerance depended on the time of first antigen administration in relation to the time of physical or chemical treatment. It is assumed that a minimal ratio between antigen and immune competent cells is an essential factor in inducing immune unresponsiveness, and predicted that, following depletion of such cells in the adult animal, much lower antigen doses would be required for induction. Thus antigen doses which are tolerogenic in newborn rabbits act similarly in adult rabbits which had undergone total-body x irradiation, or treatment with 6-mercaptopurine. However, since these treatments reduce only the numbers of immune competent cells, but have no significant influence on the general body wt or blood volume, the extracellular antigen concentration remains the same in treated and untreated rabbits. Each single competent cell is acted upon by the same concentration of antigen molecules in treated and in nontreated adult animals. This makes the significance ot the antigen-competent cell ratio difficult to explain in purely quantitative terms; possibly the physical or chemical treatment not only depletes the number of cells but also induces, following this depletion, the appearance of cells at stages particularly susceptible to induction of unresponsiveness. (BBB)

• Research Organization: Weizmann Inst. of Science, Rehovoth, Israel
• NSA Number: NSA-17-038793
• OSTI ID: 4657594
• Journal Information: Immunology (England), Journal Name: Immunology (England) Vol. Vol: 6; ISSN IMMUA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AGE
ALBUMINS
ANIMAL CELLS
ANTIGENS
BIOLOGY AND MEDICINE
BLOOD SERUM
CATTLE
DRUGS
IMMUNITY
MAN
ORGANIC SULFUR COMPOUNDS
RABBITS
RADIATION DOSES
RADIATION EFFECTS
TOXICITY
X RADIATION