Studies on the control of antibody synthesis. II. Effect of antigen dose and of suppression by passive antibody on the affinity of antibody synthesized

The effect of antigen dose on the kinetics of circulating antibody synthesis and on antibody affinity was studied in a haptenic system. High doses of antigen resulted, early in immunization, in higher concentrations of antibody followed later in the immune response by decreased serum levels of antibody as compared with lower doses of antigen. The affinity of the initial antibody synthesized was very similar over a wide antigen dose range. Subsequently, however, a rapid rise in affinity was seen in animals immunized with low doses of antigen, while relatively little change in affinity was seen in animals immunized with higher antigen doses. Suppression of active antibody formation by passive antiserum led to an increase in antibody affinity. The results are discussed in terms of the mechanisms involved in the selection of a population of cells to participate in the immune response and the mechanisms whereby antigen dose and circulating antibody function to control antibody synthesis.

Tributyltin isothiocyanate and isocyanide

Infrared evidence has been used to demonstrate that tributyltin isothiocyanate is formed when certain tributyltin compounds are reacted with inorganic thiocyanates or thiourea. Molecular refraction data supporting this contention are also reported. �� The preparation of tributyltin isothiocyanate by several different methods and of tributyltin succinimide is described.

Organotin carboxylates

The homologous series of tributyltin carboxylates ranging from the formate to the stearate and three substituted tributyltin acetates have been prepared. Examination of the infrared spectra of the compounds supports the recent view that organotin esters are covalent and chelated in character rather than ionic compounds.

Addition Compounds of Titanium

The reaction of titanium tetrachloride, chlorotitanium alkoxides, and titanium tetra-alkoxides with ammonia and pyridine has been investigated. Solid, stable, addition complexes are formed ; these react further with alcohols to give the fully substituted ester. In some of the ammonia complexes, titanium exhibits covalencies five and six.