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Biomedical subjects

R T SMITH

Publications and source records attributed to R T SMITH.

At least 19 recordsLinked to original sources
PubMed1963

THE CATABOLISM OF PROTEIN ANTIGENS IN THE NEWBORN AND MATURING RABBIT.

The rate of degradation, organ deposition, and blood clearance of SBSA, SRSA, and IRSA has been measured in the newborn, 6-, and 30-day-old rabbits. When the animals were injected with a weight-graded dose of the 3 proteins, differences in their catabolism in the newborns were demonstrable as compared to the 6-, and 30-day-old animals. The capacity to degrade the azo compounds was shown to be incompletely developed at birth. At 6 days of age, however, the rabbits catabolized these proteins much at the same rate as the 30-day-old animals. Addition of the benzenesulfonate moiety determined the rate of degradation organ deposition and excretion rather than the carrier protein when the azo compounds were injected. The biosynthetically labeled S(25) rabbit serum albumin (IRSA) was catabolized at a slower rate than the azoproteins in all age groups. Very little difference in the metabolism and organ deposition of the IRSA was shown to exist between the newborn and maturing animals. A dosage schedule, therefore, designed to test the immunological capacity of developing animals may not be valid when calculated upon body weight. The low level of activity of enzyme systems present at birth which degrade anti-genic material may serve as an explanation as to why this period of development is so vulnerable to the induction of tolerance rather than immunity when compared to the adult.

Animals↗
PubMed1963

The development of the immune response. Studies on the agglutinin response to Salmonella flagellar antigens in the newborn rabbit.

By intensive stimulation with large amounts of Salmonella flagellar antigen, newborn rabbits were induced to form high titer flagellar agglutinins usually by the 7th to 10th day of life. Characterization of the agglutinins at various times during the first 30 days of life revealed that the earliest antibody which appeared was a gamma-1 macroglobulin, and that 7S gamma-2 globulins did not appear until the 4th or 5th week of life. In contrast, the adult animals produced macroglobulin antibodies for only 3 to 5 days before the lower molecular weight variety appeared. The infant macroglobulin appears to be similar in all respects to adult macroglobulin antibodies. These data are interpreted to indicate that the newborn and adult rabbit differ in their response to this type of stimulus not in timing of macroglobulin antibody production, but chiefly in the prolonged interval, which precedes the development of the capacity for the 7S type response in the newborn animal.

Agglutinins↗
PubMed1960

The distribution of S35-labeled bovine serum albumin in newborn and immunologically tolerant adult rabbits.

The fate of injected S(35)-labeled sulfanilic acid-azoalbumin in the serum, various organs, and liver fractions was compared in the newborn and adult rabbit and in specifically unresponsive and normal adult rabbits. Exponential decay of the injected antigen without the usual immune phase of elimination was observed in newborn and unresponsive adult animals. Comparison of organ distribution of radioactivity in adults and animals injected at birth and 21 days of age showed persistence in the liver at least as long as 3 weeks in all groups (which was the time chosen for observation). The slight differences in spleen and thymus concentrations with age are of undetermined significance. Comparison of the organ distribution of antigen in unresponsive adult rabbits and in normal ones showed slight differences which were similar to those predicted from previous immunization of adults which gave low grade antibody response. There was a slight selective accumulation of antigen in the nuclear fraction of liver homogenates of unresponsive animals, but no other differences were observed.

Animals↗