THE DISTRIBUTION AND TRAFFIC OF SPECIFIC HOMOCYTOTROPIC ANTIBODY‐SYNTHESIZING CELLS IN NIPPOSTRONGYLIJS BRASILIENSIS‐INFESTED RATS

Abstract

Summary Synthesis of specific homocytotropic antibody by cells from various lymphoid and haemopoietic organs in rats infested with Nippostrongylus brasiliensis has been studied by use of homologous adoptive cutaneous anaphylaxis and compared with the kinetics of appearance in the serum and thoracic duct lymph of specific IgE antibodies. Using this technique, synthesis of specific mast cell‐sensitizing antibody has been detected in the draining lymph nodes of the lung as early as 12 days after infestation and by 14 days in the draining lymph nodes of the small intestine. Specific IgE antibody was not detected in serum unlit between 16 and 18 days after infestation. The delay in detection of antibody in the serum is at least in part due to its rapid removal from the blood, because antibody en route to the bloodstream from the gut‐associated lymphoid tissue was detected in the thoracic duct lymph plasma as early as day 12, A major traffic of homocytotropic antibody‐secreting cells has been detected in the thoracic duct lymph of the infested rats. The results are discussed in terms of the possible role of immediate hypersensitivity in the expulsion of the parasite. the origin of the IgE antibody response to the parasite and the mechanism of the potentiated reagin response.

Origins of Serum IgE and of the Homocytotropic Antibody-Secreting Cells in the Thoracic Duct Lymph of Rats Infested with <i>Nippostrongylus brasiliensis</i>

“…In MLNx rats, the dramatic increase in circulating IgE that follows infestation (2,8] did not occur, and the le vels of parasite-specific IgE antibodies in serum were significantly lower. This result is consistent with earli er observations that the MLN in Nb-infested rats con tains large numbers of cells producing IgE [5,6] and is active in synthesis of parasite-specific homocytotrop ic antibody [8], We have also found that introduction of adult Nb directly into the duodenum of intact rats produces serum IgE levels comparable with those in larval in festation [Allan and Mayrhofer, unpubl. results], sug gesting that the intestinal stage is probably the major stimulus for IgE production.…”

“…Together, these findings indicate that the MLN is probably the major source of serum IgE and serum IgE anti-parasite antibody and that its contribution is not substantially replaced by other lymphoid tissues in the MLNx rat. The modest increases in both parasite-specific and total IgE in MLNx animals may have been produced in the medi astinal lymph nodes in response to the larval phase of the parasite [8,12].…”

“…However, a recent study concluded that mesenteric lymphadenectomy did not affect the levels of parasite-specific IgE [7], We have also used this method to examine the source of serum IgE and of specific anti-parasite IgE anti bodies in Nb-infested rats and to extend previous observations [8] on the presence of specific homo cytotropic antibody-secreting cells in the thoracic duct lymph.…”

“…After the experiments had concluded, all lymphadenectomized (MLNx) rats were injected with I ml of 5% Pontamine Sky Blue subcutaneously and examined 14 days later for the presence of re sidual lymphoid tissue [101. Methods for parasite maintenance and infestation with third stage larvae, thoracic duct cannulation, as says for parasite-specific IgE by passive cutaneous anaphylaxis (PCA) and total IgE levels using a radioimmunoassay have been described elsewhere [8,11], The total IgE levels were measured with reference to standards kindly provided by Dr. H. Bazin, Brussels. Homocytotropic antibody-secreting cells specific for parasite anti gens were detected by homologous adoptive cutaneous anaphylaxis (HACA) as previously described [8].…”

Local and Systemic Factors Regulating Mucosal Mast Cells

“…Larval migration has been shown to induce early homocytotropic antibody synthesis in the regional lymph nodes of the lung [22]. It was therefore possible that sensitization of the bronchus-associated lym phoid tissue was necessary to immunologically prime for a subsequent MMC response in the gut.…”