Isolation and study of functional mast cells from lung and mesentery of the guinea pig

A method is described for the dissociation of guinea pig lung and mesentery into their component cells. The method comprises incubation of the tissues with the enzyme pronase in Ca++- and Mg++-free saline followed by mechanical dispersion and yields on average 3-8% free mast cells. These cells are morphologically intact and viable. They retain an active sensitization or can be passively sensitized. The levels of cAMP and cGMP in the whole cell suspension respond to catecholamine, histamine or cholinergic stimulation in a way similar to that observed in the corresponding undispersed tissue. Although the separation of guinea pig mast cells from other cells proved to be more difficult than the purification of rat mast cells, an inrichment of greater than 50% has been achieved. The mast cells isolated by this method proliferate in vitro and have been cultured successfully for several months.

[Increase of mast cells in the peritoneal cavity of rats treated with atopic patient's serum]

In accordance with the experiments described by the author, the injection of atopic serum and the serum of patients infected with ascaris into the peritoneal cavity of the rats produces after 24 hours an increase in mast cells of the mesentery together with vascular congestion. The experiment was made in the following way: injecting 0.5 ml. of the serum in the peritoneal cavity and the observations were made after 24 hours in the ileum-cecal mesentery. The increase of mast cells is shown to have statistical significance in atopic serum (hay fever and atopic dermatitis) as well as in serum of patients infected with ascaris lumbricoides. The increase of the mast cells is seen particularly in the vascular areas. On the other hand, the injection of non-atopic serum and inactivated atopic serum by heat (56 degrees C, 2 hours) does not produce this increase in mast cells. This phenomenon of the increase of the mast cell population which the atopic serum produces is only observed after 24 hours and not in a shorter time (20 minutes). Also we would emphasize that the increase is due only to the application of the atopic serum without any need to apply the appropriate antigen. The results obtained are as follows:A) 6 control rats--38.6 mast cells/mm2 B) 7 rats + serum of patient with hay fever--88.5 mast cells/mm2 C) 4 rats + inactivated serum (56 degrees C 2 hours) from the same patient with hay fever. 47.0 mast cells/mm2 D) 4 rats + 4 serum from non-atopic persons--38.1 mast cells/mm2 B') 6 rats + 6 serum from patients with hay fever--89.0 mast cells/mm2 C') 4 rats + 4 serums from patients with atopic dermatitis. 108.0 mast cells/mm2 D') 4 rats + 4 serums from patients with ascaris lumbricoides--116.0 mast cells/mm2. Although it is known that the serum from atopic patients and those infected with ascaris lumbricoides has a high level of IgE we cannot be sure that this increase in mast cells in the rat is produced by the human IgE. The true cause of this phenomenon is unknown.

[Tetracycline and the primary immune response]

The effect of tetracycline on proliferation of plate- and rossette-forming cells in the spleen and mesenterial lymph nodes of rats in case of the primary immune response with respect to the sheep erythrocytes was studied using the methods of Jerne, Notta and Zaalberg. It was found that tetracycline acted as an inhibitor when it was administered 48 hours before introduction of the antigen. When they were administered simultaneously its inhibiting effect decreased. When tetracycline was injected 24 hours after the antigen administration it had induced stimulation of immunogenesis. The inhibiting effect of the antibiotic was more pronounced with respect to the plate-forming cells and less pronounced with respect to the rossette-forming cells. The inhibiting effect of the antibiotic was lower in the mesenterial lymph nodes than in the spleen. The problem of independent antibody genesis in the lymph nodes is discussed.

Distributions of immunoglobulin-containing cells in alimentary tract, spleen, and mesenteric lymph node of the pig demonstrated by peroxidase-conjugated antiserums to porcine immunoglobulins G, A, and M

Peroxidase-conjugated antibody to porcine immunoglobulins A, G, and M were used in a light microscope study of the distribution of immunoglobulins and immunoglobulin-containing cells in alimentary tract, spleen, and mesenteric lymph node of the pig. Largest populations of plasma cells staining for each of the 3 immunoglobulin classes were demonstrated in the lamina propria of the intestinal tract. Immunoglobulin A cells were most numerous, and immunoglobulin A and M cells each outnumbered immunoglobulin G cells which were, however, present in considerable numbers. Both immunoglobulins A and M were demonstrated in intestinal crypt epithelial cells, indicating they have similar intracellular secretion pathways. Porcine spleen and mesenteric lymph node seem to have a minor role in immunoglobulin synthesis.

Characteristics of mesenteric lymph node cells homing to gut-associated lymphoid tissue in syngeneic mice

A subpopulation of cells in murine mesenteric lymph nodes, about 15% of those synthesizing DNA at any given time, homes specifically to the gut and mesenteric nodes of syngeneic recipients within 1 day of i.v. transfer. In contrast, cells from Oeyer's patches or peripheral lymph nodes do not. A large proportion of the B blasts which home to the small intestine has surface Ig, but lacks complement receptors. Thy-1-positive T blasts home to the gut to a lesser extent than B blasts. However, it is probable that equal fractions of B and T blasts home to mesenteric nodes. Homing is not affected by measures calculated to interfere with the combination of cell surface IgA and secretory component.

Cellular sites of immunoglobulins . VI. Localization of immunoglobulins in the human thymus

IgG-, IgM and IgA-containing cells in the human thymus and mesenteric lymph nodes were studied by direct, double-antibody immunofluorescence techniques. Ig-containing cells were identified in the thymic medulla but not in cortical or paracortical zones. About 93 percent of the medullary Ig-containing cells were IgG-containing (vs. 5 percent IgM containing and 2 percent IgA - containing). By contrast, lymph nodes contained about 53 percent IgG, 31 percent IgA and 16 percent IgM type immunocytes. In addition, Ig-containing cells were about one-tenth as numerous in thymus as in lymph nodes.

Correlation between in vitro anaphylactic histamine release from tissues and reagin titer in rat

The magnitude of antigen-induced histamine release from actively sensitized rat tissues <i>in vitro</i> was compared with the amount of specific reagin in the serum. There was no quantitative correlation between either, suggesting that the antigen-induced histamine release from sensitized tissues might depend on the ability of sensitized target cells to release histamine. In addition, the magnitude of antigen-induced histamine release was different in each tissue of sensitized rats. This also suggested that there might be some differences in the ability of sensitized target cells in each tissue to release histamine by antigen.

The suppression of rejection of Nippostrongylus brasiliensis in Lewis strain rats treated with ovine prolactin. The site of the immunological defect

Castrated male rats were treated parenterally with ovine prolactin during a primary infection with Nippostrongylus brasiliensis. Survival of the worms in the small intestine was prolonged, which suggested that prolactin inhibited rejection of the parasite.

As previous studies have shown that the mechanism of rejection of helminths is at least diphasic, comprising an immuno-specific component (antibody and lymphocytes) and an immunologically non-specific component (probably involving myeloid cells and biogenic amines), it was conceptually possible that prolactin-mediated suppression of worm expulsion was due to failure in either or both components. The site of immunological impairment in prolactin-treated animals was investigated by the technique of syngeneic lymphocyte transfer.

The functional activity of immune mesenteric lymph node cells, as assessed by their capacity to cause parasite rejection, was reduced by treatment of cell recipients with prolactin. In addition, lymphocytes from donors treated with prolactin during immunization were substantially less effective in rejecting an infection than cells from untreated donors when transferred to syngeneic recipients. These results showed that prolactin affected the immuno-specific component of the immune response. In order to exclude the possibility that prolactin could affect the immuno non-specific component of the rejection mechanism, lymphocytes from prolactin-treated immunized donors were transferred to prolactin-treated and untreated syngeneic recipients. The rejection of a challenge infection was suppressed to the same extent in both treated and untreated recipients, indicating that the main effect of prolactin is directed towards the immunologically specific lymphoid phase of the worm rejection mechanism.

Affinity of immunoglobulin for heterologous tissue mast cells. A study with the fluorescent antibody method

A double layer immunofluorescence method was used to explore the affinity of immunoglobulins and immunoglobulin fragments for the mast cells of the mouse tongue. Human IgG but not IgA or IgM showed such an affinity as revealed by fluorescence of globulin attached to the mast cell surface and to the mast cell granules. This affinity was found also in isolated H(γ) chains but not in the light chains of IgG. After papain digestion, the Fab and Fc fragments obtained showed no affinity for mouse tongue mast cells though the 5S fragment obtained after pepsin digestion retained activity. The human immunoglobulin sub-class IgG₂ lacks the ability to bind to mouse tongue mast cells. In guinea-pig serum, γ₁- but not γ₂-globulin showed an affinity for mouse tongue mast cells. It was suggested that a specific attachment site for mouse tongue mast cell surface receptors was present on the γ chain of human IgG and that this site was in a position susceptible to attck by papain hydrolysis.

The primary immune response in mice. II. Cellular responses of lymphoid tissue accompanying the enhancement or complete suppression of antibody formation by a bacterial endotoxin

The effects of a single injection of a bacterial endotoxin on the cellular changes of a primary immune response to a standard dose of sheep red blood cells were studied in the spleens and mesenteric lymph nodes of mice. Daily histological comparisons of these organs in mice, injected with endotoxin, or with antigen, or both, showed that endotoxin given simultaneously with sheep red blood cells, as antigen, significantly enhanced all of the cellular changes that appear in the mesenteric lymph nodes and spleens of mice that form antibody when that antigen is given alone. First, in the white pulp of the spleens and cortical regions of the nodes, there appeared an early and excessive proliferation of the large pyroninophilic cells which seems to be responsible for the earliest formation of antibody, as judged by this work and that of others cited in the body of the paper. Polymorphonuclear cells invaded the spleens of these animals early after simultaneous challenge with antigen and endotoxin, and in far greater numbers than have ever been seen in mice given the same antigen without endotoxin. "Activated" germinal centers formed in the lymphoid tissue either 1 day before the appearance of antibody in the blood stream or on the same day, and they became larger than in the mice given antigen only. On the other hand, these specific and characteristic cellular changes failed to appear in mice prevented from forming any antibody at all by injections of endotoxin given 2 days before the antigenic challenge. These findings are discussed in the light provided by data from recent reports of others as well as in the light of the accompanying paper (1) which demonstrated not only the enhancement of antibody formation following simultaneous injections of antigen and endotoxin, as already known, but a totally unexpected, complete suppression of its formation when endotoxin was given 2 days before antigen.