Studies on the immune response to a characterized antigenic determinant of the tobacco mosaic virus protein

The functional dissection of an antigen molecule: specificity of humoral and cellular immune responses to glucagon

Bovine glucagon, a polypeptide of 29 amino acids, was immunogenic in guinea pigs. The immunologic determinants of glucagon were investigated using isolated tryptic peptides of the hormone. Antibodies from virtually all of more than two dozen animals had specificity primarily for the amino-terminal heptadecapeptide (NM) and showed little or no binding with the carboxy-terminal undeca- and dodecapeptides (C). The smallest synthetic peptide of a series initiated at residue 16 which measurably bound antibody comprised residues 5-16 of glucagon. In cellular immune assays, both NM and C elicited delayed cutaneous reactions and inhibited the migration of peritoneal cells from immune animals. However, only intact glucagon and its C fragment stimulated lymphoid cells to synthesize DNA. While glucagon was somewhat more active than C, the addition of NM to C did not enhance its transforming activity. The smallest synthetic carboxy-terminal peptide with discernible transforming activity comprised residues 19-29 of glucagon. In both native and synthetic C peptide preparations, the undecapeptide was generally more active than the dodecapeptide, although cells from different animals gave different response patterns. The difference between the two is the presence of arginine at the amino-terminus of the peptide chain. Thus, the recognition specificity of populations of antigen-reactive cells from different animals displays a variation which is at least superficially analogous to that of populations of antibody molecules. In limited experiments using NM and C peptides as immunogens, neither gave rise to delayed hypersensitivity or to glucagon-binding circulating antibody, following a regimen which invariably provoked these responses when glucagon itself served as the immunogen. These results indicate that glucagon was cleaved by trypsin along functional lines into two parts, one of which housed the major antigenic determinant and the other of which carried the major immunogenic determinant, and they are highly compatible with a two-cell mechanism of immune induction. An apparent dissociation between the capacity to provoke delayed hypersensitivity reactions and to transform antigen-reactive cells in culture was observed.

Wiskott-Aldrich syndrome, a genetically determined cellular immunologic deficiency: clinical and laboratory responses to therapy with transfer factor

Patients with diseases associated with defects in cellular immunity, such as the Wiskott-Aldrich syndrome, characteristically have severe recurrent infections and usually succumb to overwhelming infection at an early age. This communication describes a patient with this syndrome, defective delayed hypersensitivity by skin tests and by in vitro lymphocyte response, who was treated with dialysate of peripheral blood leukocytes (transfer factor). After treatment, the clinical status of the patient improved dramatically, concomitant with the development of delayed hypersensitivity to antigens to which the donor was sensitive. In vitro tests after transfer indicated that the patient's lymphocytes, when stimulated by specific antigen, produced migration inhibitory factor without concomitant DNA synthesis. These observations dissociate skin test sensitivity and activity of migration inhibitory factor from in vitro blastogenesis. Further, the response to phytohemagglutinin remained diminished before and after therapy. While these findings represent only an individual case, the climical results suggest that investigation of the use of transfer factor appears warranted in the therapy of Wiskott-Aldrich syndrome and other genetically-determined diseases associated with impaired cellular immunity.