R.R.A. Coombs

Immediate Hypersensitivity Reactions to Cow Milk Proteins in Isolated Epithelium from Ileum of Milk-Drinking Guinea-Pigs: Comparisons with Colonic Epithelia

The epithelium lining the ileum has been isolated and studied in vitro under short-circuit conditions. Tissues were obtained from guinea-pigs fed cow milk. When challenged with beta-lactoglobulin on either the apical or basolateral side, a transient, inward flowing current was recorded. This reaction did not occur with tissues from non-milk drinking animals. Casein and alpha-lactalbumin, in contrast to beta-lactoglobulin, produced only minor effects while bovine serum albumin and bovine gamma-globulin were without effect. The effect with beta-lactoglobulin was associated with overall fluid secretion in the basolateral to apical direction, although the ions responsible for carrying the current have not been identified. Possible mediators of the response to beta-lactoglobulin have been investigated. Throughout the responses of the ileum have been compared with those in the colon. The differences between the two tissues is striking. The relevance of the model to mechanisms of food intolerance is discussed.

Recognition of the Species of Origin of Cells in Culture by Mixed Agglutination

Preliminary experiment on the mixed agglutination reaction suggests that this reaction will afford a useful method for identifying the species of origin of cells maintained in culture. n nThe reaction depends on the presence of antigens characteristic of the species, common to both tissue cells and red cells. Culture cells derived from man, ox, pig and rat could be distinguished one from the other. Fibroblasts of the mouse may be differentiated from those of the rat by means of a rat anti-mouse red-cell serum or a mouse anti-rat red-cell serum. n nExperiments are reported on trial absorption procedures to render the sera completely species-specific in their reactions.

Variation in the forssman antigen on cells in culture

Abstract Continuous lines of mouse cells growing in Forssman-negative media were found to be Forssman negative, whereas lines of dog and Chinese hamster cells were Forssman positive. One mouse cell line (NCTC929) which was grown in medium containing Forssman material, was Forssman positive, but after growth in medium containing no Forssman substance, the cells became Forssman negative. Similarly HeLa and rabbit RO/B cells, normally Forssman negative, became Forssman positive in medium containing horse serum but after two subcultures in medium not containing horse serum, reverted to Forssman negative. Four cell lines were started from mouse tissue and were grown in Forssman negative medium. The cell cultures developed into mixed populations of cells some of which were Forssman positive, while others were Forssman negative. The proportions of Forssman positive and negative cells fluctuated, and one cell line finally became completely Forssman negative.

THE REVERSIBLE “DEDIFFERENTIATION” OF EMBRYONIC SKELETAL TISSUES IN CULTURE IN RESPONSE TO COMPLEMENT-SUFFICIENT ANTISERUM

Publisher Summary This chapter discusses the reversible dedifferentiation of embryonic skeletal tissues in culture in response to complement sufficient antiserum. The drastic changes produced in cartilage and bone by complement-sufficient rabbit antisera (C’+Ab) are not necrotic, but require active and viable but physiologically deranged cells for their manifestation. The chapter presents some experiments in which thin frontal bones were exposed to very potent C’+Ab by complement-sufficient rabbit antisera, there was neither resorption of bone matrix nor increased synthesis and release of lysosomal acid protease. An important feature of the effect of C’+Ab on the skeletal tissue was the transformation of both osteoblasts and chondrocytes into a common fibroblastic form accompanied by the complete dissolution of the intercellular material. That this cytological change was a modulation, rather than a true dedifferentiation, was shown by the readiness with which the cells recovered their physiological activity when transferred to nonreactive heat-inactivated normal serum: after transfer, osteoblasts and chondrocytes reappeared and rapidly resynthesized bone and cartilage matrix. The biochemical results showed that the breakdown of intercellular material in response to C’+ Ab was associated with a much increased synthesis and release into the medium of lysosomal acid protease. Immunofluorescent staining of sections of explants for antibody adsorbed during culture on the plasma membrane of cells showed little antibody localization, except in the peripheral zones, where the staining was heavy. This indicated that little antibody reached the cells in the interior of the expiants. The immunologically mediated stimulation initiating the deranged cellular behavior may, thus, well be antibody and complement acting at the cell membrane in sub-lethal doses.