Joseph M. Davie

Mediastinal endocrine neoplasm in patients with multiple endocrine adenomatosis. A previously unrecognized association

Three cases of multiple endocrine adenomatosis (MEA) associated with a mediastinal endocrine neoplasm are presented. The mediastinal tumor was morphologically identical to the one described by us in 8 patients who did not have MEA. It behaved in an aggressive fashion and was the cause of death in all 3 cases. We regard this neoplasm as belonging to the family of carcinoid tumors and suggest an origin from the thymus gland.

Intratesticular Transplants of Islet Xenografts (Rat to Mouse)

Freshly isolated rat islets were transplanted into the testis of diabetic mice. The intratesticular islet xenografts produced normoglycemia in the diabetic recipients. The survival time of the intratesticular xenografts was significantly longer than intrasplenic, intrahepatic, and renal subcapsular sites of transplantation of xenografts of freshly isolated rat islets. Three of the recipients with intratesticular islet grafts were still normoglycemic at 60 days after transplantation, and orchidectomy resulted in a return to the diabetic state. The findings indicate that the testis provided a more privileged immunologic site than either the spleen, liver, or kidney and the lower temperature of the testis apparently did not affect the function of the islet grafts since the recipients became normoglycemic.

Subclass restriction of murine antibodies: V. The IgG plaque-forming cell response to thymus-independent and thymus-dependent antigens in athymic and euthymic mice

Abstract Antigens differ in their abilities to stimulate antibodies of various isotypes. Many thymus-independent (TI) polysaccharide antigens stimulate largely IgG3 and IgM antibodies while thymus-dependent (TD) protein antigens stimulate predominantly IgG1 and smaller amounts of other isotypes. Here we determine whether thymus dependence or independence is a property of antigens which is expressed equally by all isotypes. To do this nu /+ and nu/nu mice were immunized with several TI and TD antigens and antibody responses of IgM and the four IgG subclasses measured. We found that, within the conditions of these experiments, all IgG isotypes were influenced equally by the presence or absence of T lymphocytes. Second, in agreement with J. L. Press ( J. Immunol. 126 , 1234, 1981), we propose a division of TD antigens into two types based upon the ability to stimulate responses in the CBA/N mouse.

B cell subsets and differential responses to mitogens.

The differentiation pathways of T and B lymphocytes indicate major differences in the general organization of these lymphocyte lineages. Through detection of specific cell surface antigens, T lymphocyte differentiation appears to follow precisely defined pathways (Cantor & Boyse 1975a, 1975b) which ultimately limit the functional options of an individual T cell; a T cell can function as a helper cell (Cantor et al. 1976, Jandinski et al. 1976) or a suppressor cell (Cantor & Boyse 1975a, Cantor et al. 1976, Jandinski et al. 1976), but interconversion does not occur. By comparison, B lymphocyte differentiation is less clearly defined. Although several differentiation markers are known (Ahmed et al. 1977, Huber et al. 1977, Huber 1979, Subbarao et al. 1979), the developmental pathways of the B cell lineage are still unclear. Evidence for B cell heterogeneity is abundant; yet, at the present time, it is not possible to serologically or phenotypically define B cell maturational steps in a fashion analogous to T cells. However, it is likely that at least some of this confusion is related to the flexibility of the cells under investigation. Murine B lymphocytes have the potential to express any of eight CH genes in response to any given agent, and are also subject to a diverse array of regulatory interactions (e.g. T helper and T suppressor cells, antigen presenting cells, etc). Therefore, it should perhaps not be too surprising to find many examples of heterogeneous B cell function. Precursor analysis in limiting dilution assays (Lewis & Goodman 1977, Quintans & Cosenza 1976), expression of distinctive differentiation antigens (Ahmed et al. 1977, Huber et al. 1977, Subbarao et al. 1979), qualitative and quantitative differences in membrane immunoglobulin isotypes (Abney et ai. 1978, Scher et al. 1976a, 1976b, Vitetta & Uhr 1977), differential acquisition of immunocompetence during ontogeny (McKearn & Quintans 1979, Mosieretal. 1977), and selective inactivation following exposure

Prolongation of islet xenograft survival by in vitro culture of rat megaislets in 95% O2

Individual rat islets could be aggregated into single megaislets in vitro and the megaislets remained morphologically and functionally intact after a 7-day period of culture in the presence of 95% O2 and 5% CO2. Cultured rat megaislets transplanted beneath the renal capsule of diabetic mice produced normoglycemia in the recipients and the survival of the xenografts was markedly prolonged by the 7-day exposure to a high oxygen tension. A single injection of antilymphocyte sera to mouse and rat lymphocytes into the recipients receiving cultured megaislets did not produce a further increase in the percentage of survival of the grafts at 70 days after transplantation. Lymphoid aggregates were present around xenografts of cultured negaislets at 60 and 90 days after transplantation. This lymphoid reaction did not interfere with the function of the xenografts since the recipients were normoglycemic and removal of the grafts resulted in a rapid return to a diabetic state. Intraportal and intrasplenic transplants of cultured rat megaislets did not survive as long as the xenografts of megaislets transplanted beneath the renal capsule. The renal subcapsule site apparently provided some immunological advantage for delaying acute rejection since transplants of individual, fresh rat islets survived for twice as long under the renal capsule as compared with intraportal transplants of fresh rat islets.

Isoelectric focusing of immunoglobulins: improved methodology.

Conditions for isoelectric focusing and detecting antibodies in thin layers of polyacrylamide have been evaluated and several improvements have been made. First, we have developed a simple method for covalently attaching the polyacrylamide gel to the glass support which improves the mechanical stability of the gel and removes the need for protein subbed plates. This in turn leads to decreased electroendosmosis and decreased background protein staining. Secondly, we have applied the methods of Nguyen and Chrambach (1977 a,b), in which amino acid solutions are used as electrodes, to focus immunoglobulins. This has eliminated cathodic drift and resulted in extremely stable pH gradients. Finally, we have found that conventional methods for detecting focused antibodies that rely on protein cross-linking before exposure to antigen often lead to distortion of the focusing patterns. Both glutaraldehyde and suberimidate destroy the antigen binding capacity of some antibodies at concentrations too low for complete fixation of protein bands. These fixation artifacts are avoided if salt-precipitated antibodies are exposed to radiolabeled antigen before fixation.

Prolongation of islet allograft survival.

SUMMARY Pretreatment of donor rats with irradiation and silica followed by in vitro culture of the islets for 1 to 2 days prolonged survival of allografts across a minor histocompatibility barrier if “hand-picked,” clean islets were used for transplantation. Pretreatment of donor rats with irradiation and silica in conjunction with a single injection of antilymphocyte serum (ALS) into the recipient produced a prolongation of survival of hand-picked islets transplanted across a major histocompatibility barrier.

Prolongation of islet xenograft survival (rat to mouse) by in vitro culture at 37 C.

Meticulously selected rat islets were maintained in vitro for 7 days in a minimal volume of tissue culture medium at 37 C in air and 5% CO2. The cultured islets were transplanted into diabetic mice, either into the liver via the portal vein, or beneath the renal capsule. The survival of the cultured islets, following intrahepatic or renal subcapsular transplantation, was significantly prolonged compared with that of fresh islets. The renal subcapsular site apparently provides some additional immnnologic advantage, because the survival time of the cultured islets in this she was approximately twice as long as in the intrahepatic transplants.

Effect of Culture on Islet Rejection

In order to diminish or prevent rejection of transplanted allogeneic islets of Langerhans, in vitro culture was used. After digestion of the rat pancreas and Ficoll separation, islets were handpicked to be free of vascular and ductal tissue. Phenol red in the culture medium imparted a pink color to the islets when observed with a diffuse green light against a black background. Islets cultured at room temperature (24°C) remained functionally and morphologically intact for 1–4 wk. Insulin secretion was 1–3 μU per islet per hour, increasing to 16 μU per islet per hour at 37°C, Culture alone resulted in a modest prolongation of function across a major histocompatibility barrier, Wistar Furth to Lewis (mean survival time, 11.6 ± 1.2 vs. 7.2 ± 0.5 days). However, one injection of antilymphocytic serum (ALS) into 10 recipients at the time of transplantation prolonged survival to greater than 100 days in nine rats. In the combination ACI to Lewis, also a major barrier, the same regimen prolonged function to greater than 100 days in five out of five recipients. Injection of donor peritoneal exudate cells resulted in prompt rejection of islets. These results suggest that culture and ALS either damage or alter passenger leukocytes in the donor tissue, thereby preventing rejection Of the islets.

Detection of isoelectric focused antibody by autoradiography and hemolysis of antigen-coated erythrocytes. A comparison of methods.

Mouse anti-group A streptococcal carbohydrate (GAC) antibodies were detected in analytical isoelectric focusing (IEF) acrylamide gels by the hemolysis of GAC-coated sheep erythrocytes immobilized in agarose. This procedure is rapid and reproducible but, because it requires diffusion of antibody from the acrylamide gel into the agarose layer, results in poorer resolution than other methods of detection where antibodies can be fixed in the acrylamide gel after focusing, such as protein staining of purified antibodies or autoradiography of 125I-GAC bound to focused antibodies.