Mediators of cellular immunity, their nature and assay

[Importance of fibroblast chemotaxis in wound healing and tumor cell evasion]

Fibroblast are responsible for the synthesis of the structural proteins of the connective tissue. A further property of these cells, their migratory ability, could be analyzed in the last years. A special form of migration is chemotaxis, which can be quantitatively measured in a modified Boyden chamber in-vitro. Using this method chemoattractive substances could be characterized, which are able to stimulate fibroblasts and tumorcells to chemotactic migration. Furthermore it could be proved, that benign and transformed cell lines react in a different manner towards these chemoattractive substances. The in-vitro results allow some hypotheses about both fibroblast migration in wound healing or chronic inflammation, and the mechanisms of tumor cell evasion in the tumor surrounding tissue or the metastasizing process in other organs.

Chemotactic activity in middle ear effusions

A study of chemotactic activity in different middle ear effusions (MEE) was undertaken using a technique that has overcome some of the pitfills of previous chemotactic investigations on MEE. In the present study, neutrophils were made to migrate upwards toward a chemotactic gradient. Chemotactic activity was differentiated from increased random migration by the use of a two-filter paper system. The study indicated that directed migration or chemotaxis was present in 65% of purulent effusions, in approximately 25% to 30% of serous and seromucinous effusions, but in less than 20% of mucoid effusions. Chemotactic agents in MEE have been discussed. Chemotactic activity for neutrophils may be an important part of the inflammatory response in otitis media with effusion (OME) and responsible for the elimination of bacteria and other foreign particles. On the other hand, prolonged chemotactic activity owing to immunologic or nonimmunologic mechanisms may be responsible for the release of lysosomal enzymes and the subsequent maintenance of an inflammatory response in middle ear tissue. The exact mechanism and nature of the underlying chemotactic response for leukocytes in OME remain to be determined.

The role of regional differences in the major histocompatibility complex in the production during pregnancy of a serum factor inhibiting macrophage migration

The response by the mother to the paternal antigens of her foetus was evaluated in the rat by the production of a serum factor which inhibits macrophage migration (serum inhibitory factor, SIF). The SIF response depended upon antigenic differences controlled by genes within the major histocompatibility complex (MHC), as demonstrated by the use of congenic strains. Differences between mother and foetus within the RT1.A region of the MHC led to SIF stimulation, whereas, differences in the RT1.B region did not. The SIF response followed the course of the pregnancy: it began at the time of implantation, reached a maximum at birth and then fell precipitously. In contrast, the SIF response to skin grafting did not correlate with differences in the MHC. Thus, the antigenic factors stimulating this maternal response to foetal antigens appear to depend upon a unique type of genetic difference, and this may be a factor in the apparent immunologic privilege enjoyed by the foetus during gestation.

Angiogenic activity in culture supernatant of antigen-stimulated lymph node cells

The culture supernatant of antigen- and phytohaemagglutinin-stimulated lymph node cells contained angiogenic activity when applied to hamster cheek pouch vascular membranes. New capillary growth was observed about 7 days after such application. This activity was generated by culturing lymph node cells with antigens for at least 12 hr, while migration inhibitory factor (MIF) was detected in the culture supernatant of 6 hr cultures. The angiogenic activity was separated from blastogenic activity, clot-promoting activity and antibody activity. However, it was not completely separated from MIF by gel-filtration. The molecular weight of the angiogenic activity was estimated to be between 35,000 and 55,000 daltons.

The dermal inflammatory reaction in initial psoriatic lesions

The cellular infiltrate in the dermis of incipient psoriatic lesions was qualitatively and quantitatively evaluated using cytochemical methods for the differentiation of inflammatory cells. The greatest intensity of the dermal infiltrate was always in the center of early lesions. It was shown that most of the inflammatory cells within the perivascular areas of the upper dermis were macrophages, monocytes and lymphocytes. The number of mast cells was not increased; eosinophils and plasma cells could not be detected. Only seldom could a single or a few polymorphonuclear leucocytes be seen in lesions at a more advanced stage. These findings are discussed in the light of known immunological and functional mechanisms.