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E De Bernardo

Publications and source records attributed to E De Bernardo.

6 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↗
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↗