Immunologic methods for the identification of cell types. I. Specific antibodies that distinguish between mammary gland epithelial cells and fibroblasts

Antibodies were produced against intact mouse mammary epithelial cells and cleared fat pad fibroblasts; after appropriate absorption, two specific antibody preparations were obtained. The antimammary epithelial cell preparation did not appear to be strain- or species-specific. The antimammary fibroblast preparation recognized both mammary and fetal fibroblasts. These findings suggested that each cell type possessed distinct immunogenic components. These components were characteristic of each cell type and could be used to identify the respective cells by an immunofluorescence technique. Characterization of the antigenic component of mouse mammary epithelial cells demonstrated that this antigen was released during enzymatic cell dissociation and was regenerated underin vitro culture.

Life games and statistical models

A set of equations is obtained, which describes the rules of a class of games (life games). These games simulate the processes of growth, death, survival, and competition. The equations are nonlinear difference equations, where the degree of nonlinearity is directly related to the number of interacting neighbors. The time evolution and the development of geometric patterns can be studied starting from these equations. Extensions and generalizations, such as the introduction of stochastic elements, can easily be accommodated in the formalism. Some significant unsolved problems are noted.

Metabolically labile DNA in aseptically grown seedlings of Pisum sativum L

Pea seedlings (Pisum sativum L.) were grown aseptically in a sterile flexible film animal isolator. Radioactivity from [Me-(3)H]thymidine, supplied to the roots of the seedlings, was specifically incorporated into pea DNA. There was no incorporation into RNA or into bacterial DNA; neither was there any non-specific binding of label to carbohydrate. Much of the radioactivity incorporated into the DNA was lost during a cold chase. The loss could not be accounted for by net DNA synthesis and cell division, and is therefore taken as strong evidence for DNA turnover. The significance of these results is discussed.

Separation of mouse homocytotropic antibodies by biological screening

An attempt was made to separate mouse γ₁ antibody from mouse reaginic antibody by injecting mouse antiserum containing both antibodies into normal mice and then at 6 and 24 hours bleeding the animals and testing their sera for passive cutaneous anaphylaxis (PCA) activity. This was termed biological screening. The 2-hour homologous PCA activity was used as a measurement of mouse γ₁ and the rat PCA activity of the mouse antisera was used as a measurement of mouse reaginic antibody. These experiments showed that in vivo screening of mouse antisera containing both mouse and rat PCA activity results in removal of the rat PCA activity of these sera whereas the mouse PCA activity remains practically unchanged. It is concluded that a separation of the mouse serum PCA activity due to γ₁ antibody from that due to mouse reaginic antibody can be achieved by biological screening. Screening experiments using very early mouse antisera collected 8 days after a single antigenic stimulation resulted in the simultaneous disappearance of both homologous and heterologous PCA activity. Heating of these very early antisera resulted in complete inactivation of heterologous PCA activity and almost complete inactivation of homologous PCA activity. Absorption of these same antisera with rabbit anti-mouse γ₁ caused no change in homologous or heterologous PCA activity. It is suggested that the PCA activity of the very early antisera is due almost entirely to mouse reaginic antibody.

Inhibition by antihistamines of the vascular permeability increase induced by bradykinin

1. Mepyramine and triprolidine hydrochloride have a marked inhibitory effect on the local increase of vascular permeability induced by bradykinin.2. The anti-bradykinin effect of both antihistamines was species dependent, being evident in rabbits, rats and mice but not in guinea-pigs.

Color test for the measurement of antibody to T-strain mycoplasmas

Purcell, Robert H. (National Institute of Allergy and Infectious Diseases, Bethesda, Md.), D. Taylor-Robinson, D. Wong, and R. M. Chanock. Color test for the measurement of antibody to T-strain mycoplasmas. J. Bacteriol. 92:6-12. 1966.-A metabolic inhibition technique for the measurement of antibody to T-strain mycoplasmas was developed, based upon the ability of T-strain mycoplasmas to metabolize urea with the concomitant production of ammonia, and the ability of specific antiserum to inhibit this ammonia production. Phenol red added to the medium served as an indicator of pH change resulting from ammonia production. Specific antiserum to T-strain mycoplasma T-960 was prepared. The T-strain organism was shown to be serologically distinct from the recognized large-colony mycoplasmas. Antibody to mycoplasma strain T-960 in human sera was demonstrated with the metabolic inhibition technique.