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Biomedical subjects

E De Bernardo

Publications and source records attributed to E De Bernardo.

7 recordsLinked to original sources
PubMed1987

A study of human-human hybridomas from patients with autoimmune thyroid disease.

Human-human B-cell hybridomas were established using peripheral blood lymphocytes from patients with autoimmune thyroiditis and Graves' disease. Peripheral mononuclear cells (PMC), with or without mitogen prestimulation, were fused with HGPRT-negative human myeloma cell lines (Gm4672 and GM0462) using 44% polyethylene glycol. Developing hybridomas were screened by enzyme-linked immunosorbent assays (ELISAs) for human IgG and IgM and antibodies to human thyroglobulin (hTg) and microsomal antigen (M-Ag). A 125I-TSH binding inhibition assay was utilized for detecting antibodies to TSH receptor (TSH-R) protein. Hybridoma formation was observed only after prior mitogen stimulation of PMC. The amount of antibody secreted by the human-human hybridomas was highly variable (10 ng-100 micrograms/ml IgG/IgM). Nine and six-tenths percent of the hybrids secreted anti-hTg and 8.4% secreted anti-M-Ag. A 5% cloning efficiency was achieved, with detection of specific thyroid autoantibody secretion in one-third of the clones derived from positive hybridomas. Immunoglobulin secretion decreased with time and long-term stable clones were not achieved. Thyroid monoclonal autoantibodies to hTg, M-Ag, and TSH-R (IgG and IgM) detected during these studies were of a low affinity. In addition, antibodies were identified which exhibited marked specificity crossover between hTg, M-Ag, and nonthyroid antigens, suggesting the presence of recurrent epitopes. Such observations may help explain the multiplicity of thyroid autoantibodies in human thyroid disease and indicate a common defect in immunoregulation. We suggest that cross-reacting epitopes may be important in the derivation of thyroid-specific B-cell clones.

Antibodies, Monoclonal↗
PubMed1986

Antigen presentation in human autoimmune thyroid disease.

Monocyte/macrophage function in patients with autoimmune thyroiditis was investigated by their presentation of two distinct antigens; sheep red blood cells (SRBC) and human thyroglobulin (hTg) using in vitro systems designed for antibody induction. Purified peripheral blood monocyte/macrophages were primed by prefeeding with antigen for 60 min at 37 degrees C, washed, and co-cultured with autologous lymphocytes under a variety of incubation conditions. The most successful system employed 5% monocyte/macrophages with autologous T-B cells in the presence of the mitogen Staphylococcus aureus and B-cell differentiating factors. Under such conditions the anti-SRBC plaque-forming cell (PFC) response was amplified equally (approximately 10-fold) by SRBC-fed monocyte/macrophages in normal controls and patients with autoimmune thyroiditis rendered euthyroid with thyroxine replacement. hTg-fed monocyte/macrophages induced a 4-fold increase in anti-hTg PFC in selected patients with autoimmune thyroiditis examined under similar conditions (mean 36 +/- 3 PFC per 10(6) T-B cells). These data indicated that antigen processing by monocyte/macrophages was normal in patients with autoimmune thyroid disease.

Adult↗
PubMed1983

Antigen-specific B-cell function in human autoimmune thyroiditis.

T-B cells from the peripheral circulation of patients with autoimmune thyroiditis were cocultured with sheep red blood cells (SRBC) or soluble human thyroglobulin (Tg), a self-antigen. The B-cell mitogen, Staphylococcus aureus, combined with macrophage-derived B-cell differentiating factor, induced in vitro lymphoid activation and proliferation in the presence or absence of Tg or SRBC, which was monitored after 6 days by specific anti-Tg and anti-SRBC plaque-forming cell (PFC) responses (expressed as PFC per 10(6) T-B cells). In the presence of SRBC, significantly more anti-SRBC PFC (322 +/- 113, SE) were generated in normals (N = 5) compared with autoimmune thyroiditis patients (58 +/- 36) (N = 8) (P less than or equal to 0.001), data consistent with an antigen-specific T-cell defect. Anti-Tg PFC, not detectable in normal controls, were observed in patients in the absence (111 +/- 41) and presence (171 +/- 64) of Tg (10-1000 ng/ml). However, variable responses were noted after such coculture experiments with Tg. Three patients demonstrated amplification of anti-Tg PFC, while three showed antigen-related inhibition of anti-Tg PFC. These data indicated heterogeneity of responses to Tg antigen in patients with autoimmune thyroid disease compounded by significantly depressed antigen-specific induction mechanisms.

Adult↗
PubMed1982

Natural cytotoxicity against chemically induced neurogenic rat tumors.

The 51Cr cytotoxicity assay was modified for ethylnitrosourea (ENU) and methylnitrosourea (MNU) induced rat neurogenic tumor cell lines. Investigations on "immune" lymphoid cytotoxicity showed little cytotoxicity above normal. Alteration in the level of lymphocytotoxicity was seen immediately after injection of a highly immunogenic tumor (EA-528). Natural cytotoxicity (NC) was present against all neurogenic tumor cell lines tested and xenogenic cell lines. The level of NC activity was dependent on age, specific tumor cell line and could be increased by isolating the nylon wool non-adherent "T" cell population. Allogenic WFu rat lymphocytes were tested for NC activity in vitro against CDF tumor cells. NC activity has potential use against these tumors in vivo.

Age Factors↗
PubMed1978

Dependence of cell-mediated immune lysis of the EL-4 ascitic lymphoma on its population composition and rhythm.

Investigations on cell-mediated immune release of 51Cr from the EL-4 ascitic lymphoma showed that daily rhythmic changes can be correlated with the dominance of certain cell types in the population. Cells in compartment 1--i.e., those representing true G0, early G1, S and M--are most sensitive to effector cell attack. During the establishment 96-hour appearance cycle of the population, each day a different compartment will predominate, with corresponding variations in percent immune release. On days when spontaneous 51Cr release shows a maximum, immune release is minimal. The differences between maximal values of immune release may reach more than 300%, when findings from different days in the appearance cycle are compared.

Animals↗
PubMedDate not supplied

Functional aspects of B cell autonomy in human thyroid disease.

To evaluate the functional aspects of B cell autonomy in human autoimmune thyroiditis we examined antigen-dependent antibody secretion using specific PFC assays for total immunoglobulin and antibodies to human thyroglobulin (hTg) and SRBC. A microculture system based on S. aureus and a macrophage-derived B cell differentiating factor provided the essential data on specific antigen induction of B cells in macrophage-depleted cultures of peripheral mononuclear cells (PMC). Anti-SRBC PFC were readily induced by SRBC-antigen in normal PMC but a significant reduction in responses was observed in patients with autoimmune thyroiditis. 8 of 10 patients had anti-hTg PFC and none were observed in normal controls. However, only 3 patients showed hTg-antigen specific B cell induction. Varying mitogen and antigen concentrations, presentation of hTg in soluble or membrane bound forms, and adding helper and macrophage cell activity failed to induce specific hTg-antigen induction in the non-responsive patients. In conclusion, anti-hTg PFC were observed in the majority of patients with autoimmune thyroiditis but such B cell secretion was not usually subject to normal immunological control mechanisms. Furthermore, the reduced anti-SRBC response in patients indicated that non-specific abnormalities were also present in this organ specific disease.

Animals↗