Biomedical subjects

K L Bost

Publications and source records attributed to K L Bost.

95 records · Page 6Linked to original sources

PubMedDate not supplied

5'-3' and 3'-5' translation of the same RNA results in hydropathically similar peptides that are antigenically related.

When a single RNA sequence is read in either the 5'-3' or 3'-5 direction, the translated peptides often are hydropathically similar even though their sequences may be different. To investigate whether hydropathically similar peptides might also be antigenically related, two peptides were synthesized from the substance P anti-sense RNA transcript: CAU CAA UCC AAA GAA CUG CUG AGG CUU GGG UCG. Translation of this RNA in the 5'-3' direction and in the 3'-5' direction resulted in two different peptides. HQSKELLRLGS and AGFGVVKKPNY, respectively. As anticipated, both peptides shared similar hydropathic profiles but were quite different with respect to their sequences. To examine their antigenic relatedness, mice were immunized with either peptide, and monoclonal antibodies were produced. Using an enzyme-linked immunosorbent assay, it was possible to demonstrate that the majority of monoclonal antibodies, selected for reactivity against the original immunogen, also reacted with the other peptide. The observed binding was determined to be specific since reactivity could be blocked with either soluble peptide. Thus, we demonstrate that hydropathically similar peptides obtained from the same RNA but translated in opposite directions are antigenically related despite difference in amino acid sequences.

Amino Acid Sequence↗

PubMedDate not supplied

The cytokine-like action of substance P upon B cell differentiation.

B cells respond to a variety of effector molecules that can induce these cells to differentiate. One such molecule is the neuropeptide, substance P (SP). Previous studies have demonstrated the presence of SP receptors on lymphocytes while limited studies have been able to demonstrate the biological significance of their expression. SP has been shown to enhance IgA and IgM responses by Peyer's patch and splenic B cells. A limitation of these studies was that the direct effect of SP upon B cells was not ascertained, suggesting these B cells were stimulated via alternate mechanisms. To this end, evidence here will be discussed that SP can directly interact with clonal B lymphoma cells and highly purified splenic B cells. The data implicate SP as a late-acting B cell differentiation factor that requires an additional triggering mechanism to initiate the B cell differentiation process.

Amino Acid Sequence↗

PubMedDate not supplied

Modulation of the mRNAs encoding substance P and its receptor in rat macrophages by LPS.

Numerous soluble factors and their receptors contribute to the regulation of immune responses. An important area of investigation concerns defining the regulation of expression of such receptor/ligand pairs, since understanding such events are central in the quest to manipulate immune responses. Receptors for the neuropeptide, substance P, are present on a variety of leukocytes, and these receptor positive cells respond to in vitro stimulation with substance P in a variety of ways. Unfortunately, little is known about the regulation of expression of substance P or its receptor in leukocytes. Here we begin to address this question by examining the ability of macrophages to express mRNAs which encode substance P and its receptor. A radiolabeled oligonucleotide probe complementary to the mRNA which encodes substance P (i.e., preprotachykinin mRNA) hybridized to a 1.3 kb RNA species present in rat macrophages. In addition, the expression of this RNA could be upregulated 6 to 8 fold when macrophages were stimulated with LPS. The ability of macrophages to synthesize and secrete immunoreactive-substance P was demonstrated by incorporation of L-[35S]methionine into material from macrophage cultures which could be recognized by a monoclonal antisubstance antibody. Macrophage RNA of approximately 3.1 kb in size was capable of hybridizing with an oligonucleotide probe complementary to rat brain substance P receptors. In addition, this RNA could be upregulated when cells were exposed to LPS. Taken together, these studies suggest that the genes used by neuronal cells and macrophages to encode substance P and its receptor are similar if not identical.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMedDate not supplied

Anti-peptide antibodies recognize anti-substance P antibodies in an idiotypic fashion.

A peptide (AGFGVVKKPNY) was synthesized based on an RNA sequence complementary to the mRNA encoding substance P (Sub P). Antibodies against this Sub P complementary peptide (termed anti-C Pep antibodies) were produced by immunizing rats with peptide conjugated to the carrier protein, keyhole limpet hemocyanin. Antisera were then passed over a peptide conjugated affinity column to specifically purify the anti-C Pep antibodies. In a similar manner, anti-Sub P antibodies were produced in rabbits and made monospecific by affinity chromatography. Using a radioimmunoassay, 125I-anti-C Pep antibodies were found to bind anti-Sub P antibodies in a dose-dependent fashion. Control antibodies did not bind nor did they inhibit binding, suggesting that the interaction of the affinity purified antibodies was not due to the presence of constant region determinants. Ultimately, the idiotypic-anti-idiotypic nature of the anti-Sub P and anti-C Pep antibodies was demonstrated using a radioimmunoassay for Sub P. Anti-C Pep antibodies competed like unlabeled Sub P in the ability to block 125I-Tyr8-Sub P binding to anti-Sub P antibodies, whereas control antibodies did not. We concluded, therefore, that immunizing with this pair of complementary peptides (i.e., Sub P and C Pep) generates antibodies which are anti-idiotypic.

Amino Acid Sequence↗

PubMedDate not supplied

Presence of ACTH and its receptor on a B lymphocytic cell line: a possible autocrine function for a neuroendocrine hormone.

A mouse B lymphocytic cell line, designated BCL1, was found to produce immunoreactive ACTH and to secrete this molecule into culture supernates. The BCL1-derived ACTH induced Y-1 adrenal cells to undergo a steroidogeneic response and was eluted from gel filtration columns at a molecular weight similar to that expected for pituitary-derived ACTH. Furthermore, ACTH receptors were detected on the surface of BCL1 cells using indirect immunofluorescence and 125I-ACTH binding studies. Scatchard analysis demonstrated the presence of high and low affinity binding sites with dissociation constants of 4.5 x 10(-12) M and 2.8 x 10(-9) M, respectively. The production of both ACTH and its receptor by this B lymphocyte cell line suggests that an autocrine mechanism might be important for the maintenance of the transformed phenotype.

Adrenocorticotropic Hormone↗