Expression of the cholera toxin B subunit in the Golgi apparatus of Swiss 3T3 cells inhibits DNA synthesis induced by basic fibroblast growth factor

We attempted to express the cholera toxin B subunit (CTXB) in the Golgi apparatus of cultured mammalian cells by means of gene transfection. Complementary DNA of CTXB was ligated with the Golgi-retention signal sequence of human beta 1,4 galactosyltransferase cDNA, and the chimeric gene yielded was inserted into a mammalian expression vector. The resultant construct was transfected into COS-1 cells for transient expression and into Swiss 3T3 cells for stable expression. The expression of a fusion protein encoded by the chimeric gene was demonstrated according to the following criteria: first, detection of a protein exhibiting the expected molecular mass on Western blot analysis using an anti-CTXB antibody; second, detection of the protein located in the Golgi area by indirect immunofluoresence microscopy; and third, detection of GM1 binding activity in cell lysates. Stable transformants satisfying the above criteria were subjected to an assay for mitogen-induced DNA synthesis. These transformants exhibited significantly lower DNA synthesis than mock transfection cells on stimulation with basic fibroblast growth factor (bFGF), whereas the two types of cells exhibited similar responses to 10% fetal calf serum and other mitogens, such as epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, calcium ionophore A23187, and platelet-derived growth factor. Analysis of the binding of radio-iodinated bFGF to the cells revealed that the transformants did not exhibit a significant decrease in the binding affinity or the number of high affinity sites. These results suggest that the fusion protein specifically inhibits the bFGF signaling not at the binding step but rather at a later step(s) triggered by the binding.

Molecular genetic analysis of the human Lewis histo-blood group system. II. Secretor gene inactivation by a novel single missense mutation A385T in Japanese nonsecretor individuals

The Lewis histo-blood group system comprises two major antigens, Lewis a and Lewis b. The Lewis b antigen is a product of two fucosyltransferases, the alpha(1,3/1,4)fucosyltransferase (Lewis enzyme; Fuc-TIII) encoded by the Lewis gene and an alpha(1,2)fucosyltransferase which is not required for synthesis of Lewis a antigen. An enzyme responsible for secreting ABH antigens into body secretions (secretor enzyme) is also one of alpha(1,2)fucosyltransferases. A candidate gene encoding secretor enzyme Sec2 gene was recently cloned by Rouquier, S., Lowe, J. B., Kelly, R. J., Fertitta, A. L., Lennon, G. G., and Giorgi, D. ((1995) J. Biol. Chem. 270, 4632-4639) and Kelly, R. J., Rouquier, S., Giorgi, D., Lennon, G. G., and Lowe, J. B. ((1995) J. Biol. Chem. 270, 4640-4649) who demonstrated a G428A nonsense mutation (Trp143 to terminal codon) in Sec2 of nonsecretors. However, the G428A nonsense mutation discovered in the Sec2 gene of nonsecretors in an ethnic group other than Japanese was not found in any of 45 Japanese nonsecretors, whereas one Filipino who had been erroneously registered as a Japanese possessed the G428A mutation heterozygously. In order to explore the Sec2 gene of a Japanese population, we performed a molecular genetic analysis of the Sec2 gene on 226 Japanese individuals, 21 in a family study and 205 in a random sampling study. We discovered two novel mutations in the Sec2 gene, an A385T missense mutation (Ile129 to Phe) that results in inactivation of Sec2-encoded alpha(1,2)fucosyltransferase and a C357T silent mutation which is irrelevant to amino acid substitution, in Japanese nonsecretors. The analysis of Japanese individuals using the polymerase chain reaction-restriction fragment length polymorphism method found three alleles in the Sec2 gene, the first having no mutation, the second having a C357T mutation, and the third having both C357T and A385T mutations, which we designated as Se1, Se2, and sej, respectively. Among 226 Japanese individuals, 40 having a Le(a+b-) phenotype and 5 having a Le(a-b-) nonsecretor phenotype were homozygous for sej/sej, whereas 149 having a Le(a-b+) phenotype and 32 having a Le(a-b-)-secretor phenotype possessed at least one Se1 or Se2. The frequencies of occurrence of Se1, Se2, and sej among 410 alleles examined in a random sample of 205 Japanese individuals were 15, 46, and 39%, respectively, indicating a rather wide distribution of the sej allele in the Japanese population. The results show that the Sec2 gene really encodes the secretor enzyme alpha(1,2)fucosyltransferase and indicate that a ethnic group-specific nonsense or missense point mutation in the Sec2 gene determines nonsecretor status. The phylogenic aspect and biological significance of the Se and Le genes are discussed.

Secretory component, the receptor for polymeric immunoglobulin, has nothing to do with beta-galactosyltransferase in human milk

Secretory component (SC) in external secretions is a soluble form of the polymeric immunoglobulin-receptor that is expressed on the cell membrane of mucosal epithelial cells. beta-(1-4)galactosyl transferase (beta-GT) is an enzyme that transfers galactose to non-reducing N-acetylglucosamine residues on various glycoproteins and is present in a soluble form in secretions as well as in a membrane-bound form. beta-GT is considered to have affinity for glycoproteins, including IgA in secretion. It has been claimed that these two proteins are related to or identical with each other. In the present study, we defined that the SC and the beta-GT are each independent molecules by the following facts; (1) both molecules are separable either by antibody-affinity chromatography, conventional ion-exchange or molecular exclusion chromatography, (2) conventionally purified SC from human milk contained neither enzymatic activity or antigenic determinants of the beta-GT, (3) recombinant beta-GT does not show reactivity with antibodies to SC, and (4) the SC showed no reactivity with antibody to beta-GT.

Golgi localization and in vivo activity of a mammalian glycosyltransferase (human beta1,4-galactosyltransferase) in yeast

Gene fusions encoding the membrane anchor region of yeast alpha1, 2-mannosyltransferase (Mnt1p) fused to human beta1, 4-galactosyltransferase (Gal-Tf) were constructed and expressed in the yeast Saccharomyces cerevisiae. Fusion proteins containing 82 or only 36 N-terminal residues of Mnt1p were produced and quantitatively N-glycosylated; glycosyl chains were shown to contain alpha1,6-, but not alpha1,3-mannose determinants, a structure typical for an early Golgi compartment. A final Golgi localization of both fusions was confirmed by sucrose gradient fractionations, in which Gal-Tf activity cofractionated with Golgi Mnt1p activity, as well as by immunocytological localization experiments using a monoclonal anti-Gal-Tf antibody. In an in vitro Gal-Tf enzymatic assay the Mnt1/Gal-Tf fusion and soluble human Gal-Tf had comparable Km values for UDP-Gal (about 45 microM). To demonstrate in vivo activity of the Mnt1/Gal-Tf fusion the encoding plasmids were transformed in an alg1 mutant, which at the non-permissive temperature transfers short (GlcNAc)2 glycosyl chains to proteins. Using specific lectins the addition of galactose to several yeast proteins in transformants could be detected. These results demonstrate that Gal-Tf, a mammalian glycosyltransferase, is functional in the molecular environment of the yeast Golgi, indicating conservation between yeast and human cells. The in vivo function of human Gal-Tf indicates that the yeast Golgi is accessible for UDP-Gal and suggests strategies for the construction of yeast strains, in which desired glycoforms of heterologous proteins are produced.

[Molecular biology of Lewis antigens--histo-blood type antigens and sialyl Lewis antigens as tumor associated antigens]

The biosynthetic pathways of the Lewis histo-blood type antigens, Lewis a (Le(a)) and Lewis b (Le(b)), in correlation with ABH antigen synthesis and the synthesis of sialyl Lewis antigens, sialyl Lewis a (sLe(a)) and sialy Lewis x (sLe(x)), known as tumor associated antigens are described based on the recent molecular biological studies. Individuals are divided by their erythrocyte Lewis antigen phenotypes into three types, Le (a+b-) which has Le(a) antigen but not Le(b) antigen, Le (a-b+) which has Leb but not Le(a), and Le (a-b-) having neither Le(a) nor Leb. It was verified that Le (a-b-) individuals are the homozygotes with the nonfunctional Lewis gene (Le gene) which is inactivated by the missense mutations. Two kinds of the inactivated Le gene alleles were found in the Japanese population, and named le1 and le2. Individuals having a Le (a+b-) or a Le (a-b-) -non-secretor phenotype are the mutants who lack the secretor enzyme (Se enzyme) activity. The Se gene encoding the Se enzyme has been recently cloned and analyzed for the mutation resulting in inactivation of the Se enzyme of the non-secretor individuals. Our Se gene mutant analyses on the Japanese population ensured that the Se gene is responsible for synthesis of the Le(b) antigen. Mutant analyses of the other genes, H gene and FucTVI gene, which are also involved in the synthesis of Lewis antigens are described. We recently demonstrated that the sLe(a) antigen is the product of the Lewis gene since all le/le patients, who are determined as the genuine Lewis negative individuals by Le genotyping, did not express any kinds of type 1 chain Lewis antigens (Le(a), Le(b), and sLe(a)) in their digestive organs. It is, therefore, unuseful to measure the CA19-9 titer of the genuine Lewis negative cancer patients.

Genetic evidence for the Lewis enzyme, which synthesizes type-1 Lewis antigens in colon tissue, and intracellular localization of the enzyme

To determine whether the Lewis enzyme responsible for the Lewis blood type antigens on erythrocytes synthesizes the Lewis antigens on normal cells and cancer cells in colon tissue, we performed genotyping of the Lewis gene by the PCR-RFLP method and by immunohistochemical staining of Lewis antigens and the Lewis enzyme with specific monoclonal antibodies (mAbs) in colon tissues obtained from 100 colon cancer patients. Five of the 100 patients were identified as homozygotes for the mutant Lewis gene, i.e., the le/le genotype that cannot encode functional Lewis enzyme. The cells in both the normal and cancerous regions of colon tissue from these five le/le patients were completely devoid of staining with mAbs against Lewis antigens with the type 1 chain, i.e., Lewis a, Lewis b, and sialyl Lewis a. In contrast, the cells in cancerous regions of the colon tissue of the 95 patients with the Le/Le or Le/le genotype positively stained with all three mAbs, anti-Lewis a, anti-Lewis b, and anti-sialyl Lewis a. The cells in the cancerous regions of the colon tissue of the five le/le patients stained with DU-PAN-2 mAb, whose recognizing epitope is known to be sialyl Lewis c, a precursor structure of sialyl Lewis a. By immunohistochemical staining with FTA 1-16 mAb, which is directed at the human Lewis enzyme, we were able to demonstrate for the first time that the enzyme is localized in the Golgi area of the colon epithelial cells of patients with the Le/Le or Le/le genotype. No staining was observed in the Golgi area of the cells of the patients with the le/le genotype. From these results, we conclude that individuals with the Le/Le or Le/le genotype possess a functional Lewis enzyme synthesizing fucosylated type-1 Lewis antigens in the Golgi apparatus of the colon epithelial cells, but that individuals with the le/le genotype are devoid of the Lewis enzyme in the Golgi apparatus, resulting in an inability to synthesize Lewis antigens with the type-1 chain, and that it is inappropriate to use CA19-9, whose antigenic epitope is defined as sialyl Lewis a, as a tumor marker in patients with the le/le genotype.

Murine monoclonal antibody recognizing human alpha(1,3/1,4)fucosyltransferase

We prepared a mouse monoclonal antibody, FTA1-16, that specifically recognizes human alpha(1,3/1,4)fucosyltransferase without crossreactivity to any other members of the alpha(1,3)fucosyltransferase family. The specificity was confirmed by both immunofluorescense staining of native antigens in the Golgi apparatus and Western blotting analysis, using stable transformant cells transfected with each gene of the alpha(1,3)fucosyltransferase family. Western blotting analysis on a series of human tumour cell lines from various tissues revealed that some epithelial cancer cell lines from digestive organs expressed an amount of alpha(1,3/1,4)fucosyltransferase in good correlation with expression of sialyl Lewis a antigen. Immunohistochemical staining by FTA1-16 on colon cancer tissues revealed enhanced expression of the enzyme in cancer cells in comparison to normal cells. Finally, the antigenic epitope recognized by FTA1-16 was determined using truncated recombinant peptides which were expressed in E. coli. A minimal length determined was a fragment, amino acid positions 132-153, of the alpha(1,3/1,4)fucosyltransferase.

[Glycosyltransferase genes for synthesis of Lewis antigens]

Biosynthetic pathways of Lewis antigens with type 1 and type 2 chains were described on the molecular genetic basis of glycosyltransferases involved in synthesis of the antigens. The analysis of Lewis-gene (Le gene) genotyping revealed that the Le gene is responsible not only for synthesis of Lewis antigens on erythrocytes (Le(a) and Leb antigens) but also for synthesis of the Lewis antigens with type 1 chain, Le(a), Leb and sLea antigens, in digestive organs. Among an a1,3 fucosyltransferase family, FucT VI is a candidate more responsible for synthesis of sLex antigen in intestinal cancer cells than the other a1,3 fucosyltransferases. Molecular genetic analysis on Se gene is now under progress to distinguish the genotypes of Le (a+ b-) individuals from Le(a- b+) individuals in the Japanese population. Individual polymorphism of Lewis antigens is determined by point mutations of glycosyltransferase genes, as proved in ABO, Le, Se, H and FucT VI genes, involved in biosynthetic pathways of the antigens.

The beta 1,4-galactosyltransferase gene is post-transcriptionally regulated during differentiation of mouse F9 teratocarcinoma cells

Mouse F9 teratocarcinoma cells converted into primitive endoderm and parietal endoderm-like cells when treated with retinoic acid (RA) and RA plus dibutyryl cyclic AMP (dbtcAMP), respectively. The carbohydrate chains of glycoconjugates are known to undergo rapid changes during F9 cell differentiation. The mechanism of gene regulation of beta 1,4-galactosyltransferase (beta 1,4GalT), one of the glycosyltransferases involved in the synthesis of carbohydrate structures, was explored during the differentiation of F9 cells. Northern blot analysis revealed that the amount of beta 1,4GalT mRNA increased approximately 1.5- and 6.5-fold in response to treatment with RA alone and RA plus dbtcAMP (RA/dbtcAMP), respectively, for 8 days. beta 1,4GalT specific activity also gradually increased up to 21-fold in response to treatment with RA/dbtcAMP for 8 days. The reason for the different rates of increase in mRNA and enzyme activity remains to be determined. The transcriptional activity of the beta 1,4GalT gene was measured during the course of RA/dbtcAMP-induced F9 cell differentiation in transient transfection experiments using 5'-upstream region DNA (1.8 kb) of the mouse beta 1,4GalT gene combined with luciferase cDNA. Although activity was slightly enhanced on the first day after induction, no significant rise in transcriptional activity was observed in the late stage of induction (3-6 days), when mRNA levels were greatly increased. This was further supported by the nuclear run-off assay which indicated that the rate of de novo synthesis of the beta 1,4GalT gene transcript in the RA/dbtcAMP-induced cells was almost the same as in undifferentiated F9 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA sequencing of the gene encoding a bacterial superantigen, Yersinia pseudotuberculosis-derived mitogen (YPM), and characterization of the gene product, cloned YPM

Previously, we found a novel bacterial superantigen from Yersinia pseudotuberculosis, designated Y. pseudotuberculosis-derived mitogen (YPM). In the present study, we analyzed the DNA sequence of the gene encoding YPM. The YPM gene was cloned into a plasmid vector pMW119 and expressed in Escherichia coli DH10B. Like the native YPM, the cloned YPM required the expression of MHC class II molecules on accessory cells in the induction of IL-2 production by human T cells. TCR-V beta repertoire of human T cells reactive with the cloned YPM was V beta 3, V beta 9, V beta 13.1, and V beta 13.2. This repertoire is the same as that of T cells reactive with the native YPM. These results indicate that the cloned YPM expressed in E. coli is identical to the native YPM. Sequencing of the YPM gene revealed that the gene contained an open reading frame of 456 base pairs encoding a precursor form of 151 amino acid residues with m.w. 16,679 that is processed into a mature form of 131 amino acid residues with m.w. 14,529. Homology analysis revealed that the homology of amino acid sequence is quite low among YPM and other well known bacterial superantigens. We designated the gene encoding YPM as ypm.

DNA sequencing of the gene encoding a bacterial superantigen, Yersinia pseudotuberculosis-derived mitogen (YPM), and characterization of the gene product, cloned YPM

Previously, we found a novel bacterial superantigen from Yersinia pseudotuberculosis, designated Y. pseudotuberculosis-derived mitogen (YPM). In the present study, we analyzed the DNA sequence of the gene encoding YPM. The YPM gene was cloned into a plasmid vector pMW119 and expressed in Escherichia coli DH10B. Like the native YPM, the cloned YPM required the expression of MHC class II molecules on accessory cells in the induction of IL-2 production by human T cells. TCR-V beta repertoire of human T cells reactive with the cloned YPM was V beta 3, V beta 9, V beta 13.1, and V beta 13.2. This repertoire is the same as that of T cells reactive with the native YPM. These results indicate that the cloned YPM expressed in E. coli is identical to the native YPM. Sequencing of the YPM gene revealed that the gene contained an open reading frame of 456 base pairs encoding a precursor form of 151 amino acid residues with m.w. 16,679 that is processed into a mature form of 131 amino acid residues with m.w. 14,529. Homology analysis revealed that the homology of amino acid sequence is quite low among YPM and other well known bacterial superantigens. We designated the gene encoding YPM as ypm.

Genetic and enzymatic evidence for Lewis enzyme expression in Lewis-negative cancer patients

It has been observed that the frequency of individuals with Lewis-negative erythrocytes is significantly higher in cancer patients than in healthy controls. In this study, 20 of the 66 (30.3%) patients with various cancers were typed as Lewis negative from their erythrocytes, while the same frequency in healthy controls was 11.1%. These 20 patients were divided into three groups based on the presence of Lewis blood group antigens and alpha 1-->4-fucosyltransferase in their salivas: group I, 6 patients who had both Lewis antigens and alpha 1-->4-fucosyltransferase activity; group II, 8 patients who had no Lewis antigens but possessed alpha 1-->4-fucosyltransferase activity; group III, 6 patients who had neither Lewis antigens nor alpha 1-->4-fucosyltransferase activity. The genotyping of Le genes by the PCR-RFLP methods, which have been developed and established by us recently, demonstrated that all 14 patients from groups I and II possess Le gene homozygously (Le/Le) or heterozygously (Le/le), whereas all 6 patients from group III were le/le homozygotes. Only the 6 patients from group III were identified as the genuine Lewis-negative individuals. The immunohistochemical staining of the colorectal tumors also showed that the Lewis antigens could be detected on the tumors from groups I and II but not from group III.

Molecular genetic analysis of the human Lewis histo-blood group system

The expression of Lewis histo-blood group antigen is determined by the Lewis type alpha(1,3/1,4) fucosyltransferase encoded in Fuc-TIII gene (Le gene) on chromosome 19. Weak hemagglutination reactions are often observed in the Lewis blood typing to cause false-negative reactions. The level of CA19-9 tumor marker, defined as sialylated Le(a) (sLe(a)), is influenced by the Lewis blood phenotype. The sLe(a) antigen is also considered to play a role in hematogenous metastasis of tumor cells. The accurate genotyping of Fuc-TIII gene would be, therefore, necessary for solving above questions. In addition to the two missense mutations previously reported by us, i.e. the T59G and the G508A, further sequence analyses revealed a new single base substitution, the T1067A, changing the Ile356 to Lys in the catalytic region. Polymerase chain reaction-restriction fragment length polymorphism methods were developed for the detection of these three missense mutations and applied in 15 Lewis negative (le/le) and 65 Lewis positive individuals (Le/Le or Le/le). These methods were found to be useful for genetic diagnosis for the Lewis histo-blood typing. All le alleles had the T59G mutation, whereas none of the Le alleles did. The le alleles were divided in two types, le1, having the G508A mutation, and le2, having the T1067A mutation. The T1067A mutation reduced the enzyme activity less than 10%, whereas the G508A mutation in the catalytic domain made the enzyme completely inactive. The frequency of occurrence of Le, le1, and le2 in the Japanese population by random sampling study was found to be 66, 30, and 4%, respectively.

Alpha (1,3/1,4)fucosyltransferase (FucT-III) gene is inactivated by a single amino acid substitution in Lewis histo-blood type negative individuals

Human alpha (1,3/1,4)fucosyltransferase (FucT-III) genes were cloned from genomic DNAs of seven Lewis negative (Le(a- b-)) individuals. Restriction mapping analyses revealed that an additional Pvu II site was created in the FucT-III genes from Lewis negative individuals. Four of these individuals were shown to be heterozygous for the Pvu II site and three were homozygous for it. The Pvu II site was produced by a single base substitution at the 508 nucleotide of coding sequence, G to A, resulting in the amino acid substitution, Gly to Ser at position 170. Another single base substitution, resulting in the change of Asp to Ala at position 336, was observed in the Lewis negative FucT-III gene which did not have the Pvu II site. The FucT-III enzyme was inactivated by these two mutations resulting in a single amino acid substitution in the catalytic region. All FucT-III genes, regardless of the Pvu II site, from Lewis negative individuals had a single base substitution, the T at position 59 to G, resulting in the change of Leu to Arg at position 20. This mutation, however, was not responsible for FucT-III gene inactivation.

Kinetic study of human beta-1,4-galactosyltransferase expressed in E. coli

Recombinant beta-1,4-galactosyltransferase which synthesizes the Gal beta 1-->4GlcNAc group of glycoprotein sugar chains was obtained as a soluble form from Escherichia coli by transfection of the human cDNA lacking the transmembrane segment. Kinetic study revealed that the soluble transferase has the same apparent Km values toward sugar nucleotide and sugar acceptors as those of mouse membrane-bound beta-1,4-galactosyltransferase previously characterized [Nakazawa et al. (1991) Eur. J. Biochem. 196, 363-368]. However, the Vmax value of this transferase was low when compared to that of the mammalian transferase, probably due to the instability of the transferase caused by the lack of protein glycosylation. The soluble transferase was purified from the E. coli lysates almost to homogeneity by chromatography on DEAE-Sepharose and alpha-lactalbumin-Sepharose columns. Using this purified transferase, the acceptor specificity of the transferase has been studied. The results showed that the transferase has apparent Km values of 170, 190, and 830 microM for agalacto-poly-N-acetyllactosamine, lacto-N-triose II, and lacto-N-triaosylceramide, respectively, but has apparently no activity toward glucosylceramide. These results suggest that the beta-1,4-galactosyltransferase may be involved in the synthesis of poly-N-acetyllactosamine, lacto-N-neotetraose, and probably lacto-N-neotetraosylceramide in addition to the formation of the Gal beta 1-->4GlcNAc group of glycoprotein sugar chains and lactose.

Human alpha-1,3 fucosyltransferase (FucT-VI) gene is located at only 13 kb 3' to the Lewis type fucosyltransferase (FucT-III) gene on chromosome 19

Human alpha-(1.3/1,4) fucosyltransferase (FucT-III) gene and alpha 1,3 fucosyltransferase (FucT-VI) gene were found in the 38-kb fragment isolated from a human cosmid library. These genes were present 13 kb apart in tandem orientation. The FucT-III gene has already been mapped on the Lewis locus of chromosome 19. This demonstrated that FucT-VI gene was localized close to the Lewis locus on chromosome 19.

Mouse monoclonal antibodies which recognize a human (beta 1-4)galactosyl-transferase associated with tumor in body fluids

Mouse monoclonal antibodies against human (beta 1-4)galactosyl-transferase (GalT) purified from human ovarian tumor effusion fluids were prepared and characterized. GalT purified from normal human plasma showed a single diffused band in nondenaturing polyacrylamide gel electrophoresis, but GalT purified from human ovarian tumor effusion fluids showed several oligomeric bands and a monomeric band in nondenaturing polyacrylamide gel electrophoresis. These oligomeric bands were dissociated into monomer by urea treatment and polymerized by a 2-mercaptoethanol treatment. Nine monoclonal antibodies (MAb) were prepared by immunization of purified GalT from human ovarian tumor effusion fluids and classified into three groups. Type I MAbs (MAb8611, MAb8913, and MAb8919) reacted only to the GalT monomer. Type II MAbs (MAb4880, MAb8507, and MAb8628) reacted to both the GalT monomer and the GalT polymer. Type III MAbs (MAb7907, MAb8513, and MAb8677) reacted only to the GalT polymer. These MAbs except MAb7907 could recover GalT enzyme activity from effusion fluids by immunoprecipitation. A fraction passed through MAb8513 affinity chromatography still showed reactivity to MAb8919, demonstrating that an epitope of MAb8513 resides on a minor part of GalT. A sandwich immunoassay (MAb8513-MAb8628HRP) was developed, and serum samples from ovarian cancer patients and benign ovarian patients were tested. The levels of sandwich immunoassay of serum samples from cancer were elevated significantly compared to those from benign and did not necessarily correlate to total GalT enzyme activity in serum samples. These results suggested that MAb8513 (Type III) might recognize a unique GalT associated with tumor (GAT).

Complementary DNA cloning for galactosyltransferase associated with tumor and determination of antigenic epitopes recognized by specific monoclonal antibodies

The galactosyltransferase associated with tumor (GAT) was the name given to the isoenzyme that tends to polymerize resulting in slower moving in a nondenaturing polyacrylamide gel electrophoresis than normal (beta 1-4)galactosyltransferase (normal GalT). A complementary DNA (cDNA) library was constructed from a human ovarian cancer cell line, RMG-I, which secreted an amount of GAT into the culture supernatant and screened with monoclonal antibodies (MAbs) against GAT and normal GalT. One of six cDNA clones, UG86-1, encoded an epitope recognized by a GAT-specific MAb, 8513. Recombinant proteins expressed by UG86-1 in Escherichia coli also had antigenic epitopes recognized by the other MAbs against normal GalT. The 229-base pair nucleotide sequence encoded by UG86-1 was identical to the stem region sequence of HGT832 which encodes a full-length cDNA of human GalT. Using recombinant proteins directed by deletion mutant cDNAs, the antigenic epitopes recognized by each MAb were determined. The epitope of MAb8628, which reacts to both the GAT and normal GalT, was localized to the COOH-terminal side of proteolytic cleavage site where the membrane-bound form enzyme is cleaved to be converted to soluble forms, while MAb8513 epitope was at the NH2-terminal side from this cleavage site between the COOH-terminal end of the membrane-binding domain and the cleavage site. These results demonstrate that GAT is produced by aberrant proteolytic cleavage at the different site, closer to the membrane-binding domain, from the normal GalT.

[Vecuronium-induced neuromuscular blockade in two patients with hyperparathyroidism and a patient with hypoparathyroidism]

Vecuronium-induced neuromuscular blockade was evaluated in two patients with primary hyperparathyroidism and in a patient with hypoparathyroidism. A 39 year old male with typical primary hyperparathyroidism was scheduled for surgical removal of the parathyroid adenoma. Serum levels of calcium and ionized calcium were 15.0 mg.dl-1 and 1.95 mmol.l-1, respectively. A 44 year old female suffering from primary hyperparathyroidism was also scheduled for surgical removal of the adenoma. Serum levels of calcium and ionized calcium were 12.5 mg.dl-1 and 1.51 mmol.l-1, respectively. A 63 year old male, suffering from postoperative secondary hypoparathyroidism and treated with calcium, was scheduled for surgical removal of the recurrent pharyngeal cancer. Serum levels of calcium and ionized calcium were 9.0 mg.dl-1 and 1.15 mmol.l-1, respectively. Anesthesia was induced with thiamylal 4-5 mg.kg-1 and vecuronium 0.08 mg.kg-1 and was maintained with 70% nitrous oxide in oxygen and fentanyl in all three patients. Neuromuscular blockade following the administration of vecuronium was measured by a big toe abduction evoked by supramaximal stimulation of the tibial nerve (Myograph 2000, Biometer, Denmark). In order to evaluate the effect of serum calcium level on vecuronium neuromuscular blockade, ten patients with normal serum levels of calcium, were examined in the same fashion. In only one patient with hyperparathyroidism, whose serum calcium was 15.0 mg.dl-1, the onset and the duration of vecuronium were later and shorter than those of other patients with normal serum levels of calcium. In conclusion, we should pay attention to the antagonistic responses to vecuronium in patients with severely high levels of serum calcium.

Multiple pulmonary nodules caused by zygomycosis in a patient without predisposing factors

We report a case of a 61-year-old male without any predisposing factors. His X-ray film showed multiple nodular lesions in bilateral lung fields. Open lung biopsy revealed Zygomycetes in the granuloma. The patient was treated with amphotericin B and miconazole, and remains alive more than 32 months later.

Changes in K(+)-induced contractions in ileal longitudinal smooth muscle of guinea-pig, induced by monoiodoacetic acid

The ileal responses to 40 mM [K+]o were changed in the period after administration of monoiodoacetic acid (IAA). The phasic contraction to K+ appeared in the period before the development of a rigor, after the administration of 1 mM IAA. However, the response to K+ was absent during the development of a rigor to IAA during decreasing tissue ATP concentrations.

HLA class II antigens are associated with Japanese pemphigus patients

We investigated the HLA class II antigens in 30 Japanese cases of pemphigus, 17 cases of pemphigus vulgaris (PV) and 13 cases of pemphigus foliaceus (PF), by both serologic and restriction fragment length polymorphism (RFLP) analyses. We detected two major haplotypes susceptible to PV, i.e., DRw12-DQw7 and DRw6-DQw5. In contrast, DR2 was absent in PV. RFLP analyses showed that DRw6 PV patients had a disease-associated restriction fragment representing DQw5, the same association as that found in DRw6 Jewish PV patients. However, DRw12 Japanese PV patients had DQw7, whereas DR4 Jewish PV patients had DQw8. On the other hand, all 13 PF patients were serologically typed for DQw1, which could not be further subdivided into DQw5 by RFLP analyses. These results suggest that Japanese and Jewish PV patients may be immunogenetically closely related to each other, but Japanese PV patients appear to be immunogenetically different from Japanese PF patients.

Characterization of a murine beta 1-4 galactosyltransferase expressed in COS-1 cells

We inserted a full-length murine cDNA, which had been isolated from F9 embryonal carcinoma cells by using a bovine lactose synthetase A protein cDNA as a probe, in a mammalian expression vector (pCMGT1) and expressed it in COS-1 cells to characterize the pCMGT1-directed enzyme. The galactosyltransferase activity toward asialo-agalacto-transferrin (AsAg-Tf) in the pCMGT1-transfected cells was approximately eightfold higher than that in mock- or non-transfected cells. In contrast, no difference was observed in the specific activity of galactose transfer between pCMGT1-transfected cells and mock- or non-transfected cells when asialo-ovine submaxillary mucin were used as an acceptor. Since almost all [3H]galactose incorporated into the AsAg-Tf was released by digestion with streptococcal beta-galactosidase, most of the linkage created by this enzyme was in the Gal beta 1-4GlcNAc group. The acceptor specificity of the pCMGT1-directed enzyme was changed from N-acetylglucosamine to glucose by adding alpha-lactalbumin in the reaction mixture. Alpha-Lactalbumin also partially inhibited the galactose transfer to AsAg-Tf. The kinetic study revealed that the apparent Km values of the pCMGT1-directed enzyme for N-acetylglucosamine, AsAg-Tf and UDP-Gal are 2 mM, 60 microM and 24 microM, respectively. These results indicated that the murine cDNA isolated from F9 cells encodes an active enzyme which catalyzes not only the lactose synthesis but also the transfer of galactose to N-acetylglucosamine residues of Asn-linked sugar chains of glycoproteins in a beta 1-4 linkage.

[A case of so-called carcinosarcoma of the lung]

A 66-year-old woman was admitted to hospital because of a persistent cough and hemoptysis. Her chest X-ray showed a coin lesion in the S10 area of her right lung. The tumor was resected and its histologic features showed it to be a so-called carcinosarcoma of the lung.

Cloning and sequencing of a full-length cDNA of mouse N-acetylglucosamine (beta 1-4)galactosyltransferase

A full-length cDNA clone for mouse N-acetylglucosamine (beta 1-4)galactosyltransferase (beta 1-4GT) [EC 2.4.1.90] and several clones diverged from the beta 1-4GT cDNA were isolated from a mouse F9 cDNA library and then sequenced. The beta 1-4GT cDNA has an open reading frame consisting of 399 amino acids. The homology at the amino acid level is 80 and 91% as to the partial sequences of bovine and human milk beta 1-4GT, respectively. The general enzyme structure of the beta 1-4GT seems to be similar to that of a rat beta-galactoside (alpha 2-6) sialyltransferase. Junctions of the common and divergent regions of cDNA have dinucleotides, AG, suggesting that the variety of cDNA clones is generated through alternative splicing.

Induction of cutaneous graft-versus-host disease by allo- or self-Ia-reactive helper T cells in mice

Recent evidence suggests that Ia+ Langerhans cells may be a primary target for destruction in cutaneous graft-versus-host disease (GVHD). Although it is generally accepted that T lymphocytes with helper/inducer phenotype are essential, the identity of the effector cells is still controversial. We therefore investigated whether a variety of Ia-reactive cloned helper T cells with different cross-reactivities and functions in vitro can induce cutaneous GVHD following intradermal inoculation into the footpad of the appropriate recipients, whose Ia antigens are able to stimulate the T cells to proliferate in vitro. All cloned T cells tested caused significant footpad swelling in their appropriate recipients with a course typical for local cutaneous delayed-type hypersensitivity (DTH) reactions. Two of these cloned T cells, SK 1 and BB5, induced local histologic changes consistent with grades 2-3 of cutaneous GVHD in the appropriate allogeneic or syngeneic recipients at 48-72 hr after their intradermal inoculation. Immunohistochemical studies using monoclonal antibodies demonstrated that not only injected cloned T cells but also Lyt-1+ cells derived from the recipient migrate into the epidermis and are responsible for the destruction seen in cutaneous GVHD. In epidermis in which cutaneous GVHD had been induced, expression of Ia by keratinocytes and the damage of Ia+LC were observed. These results suggest that Ia+LC and Ia+ keratinocytes may play an important role in the infiltration of Ia-reactive T cells responsible for cutaneous GVHD.

Effect of orally administered aromatic retinoid on murine Langerhans cells

The effect of orally administered aromatic retinoid (Ro 10-9359) on murine epidermal Langerhans cells (LC) was studied in vivo and in vitro. Daily administration of retinoid caused a transient increase in LC density, as determined by staining for Ia antigens, during the first few days of treatment and thereafter a continuing decrease that reached a maximum at 2 weeks. In addition, the morphology and location in the epidermis had been altered. When the treatment was continued to 4 weeks, the density of LC returned to normal. The Ia-antigen-presenting function of epidermal cells to an allo-Ia-reactive cloned T cell line was elevated at all stages of retinoid treatment examined. This elevation did not correlate with the density of histochemically stainable Ia+ LC. These findings suggest that orally administered retinoid profoundly alters the functional capacity of Ia+ LC.

Cloned auto-Ia-reactive T cells elicit lichen planus-like lesion in the skin of syngeneic mice

To explore the physiologic or pathologic roles of autoreactive T cells, we examined immunological functions of several autoreactive mouse T cell clones in vitro and in vivo. All of the T cell clones were Lyt-2-, L3T4+ and showed self-I region-restricted proliferative responses (one clone was self-I-E restricted, the other clones were self-I-A restricted). One clone derived from C57BL/6 mouse and reactive to the self-I-Ab product (clone bb1-2) showed cross-reactivity to the I-Ak product. Among four such auto-Ia-reactive T cell clones examined, one clone produced fairly large amounts of interleukin 2 (IL 2) in response to syngeneic stimulator cells, and mediated help for the in vitro cytotoxic T cell (CTL) responses of syngeneic thymocytes, whereas this clone did not mediate in vitro antibody responses of syngeneic B cells. The other three clones were producers of small amounts of IL 2 and did not mediate the in vitro CTL responses. Among the three clones, clone bb1-2 showed strong regulatory function, and clone kk-1 (B10.BR origin and self-I-Ak reactive) showed weak regulatory function in vitro antibody responses of syngeneic B cells. The physiologic or pathologic roles of autoreactive T cells in vivo were explored by injecting subcutaneously clone kk-1 T cells or clone bb1-2 T cells into the footpads of the respective syngeneic mice. Clone kk-1 T cells injected into syngeneic mice elicited swelling of the footpad and marked accumulation of mononuclear cells in the dermis, leaving the epidermis intact, as in the delayed-type hypersensitivity reaction. As a notable finding, clone bb1-2 T cells injected into syngeneic mice elicited marked swelling of the footpad and lichen planus-like skin lesions, i.e., infiltration of lymphocytes in the epidermis and epidermal cell damage. The lymphocytes infiltrating in the epidermis were evaluated, as were the injected clone bb1-2 T cells expressing the Lyt-1.2 phenotype, by examination of the skin lesions elicited in C3H/He mice (H-2k, Lyt-1.1, 2.1) by the clone T cells. Clone bb1-2 T cells exerted in vitro cytotoxicity against H-2b and H-2k target cells, whereas clone kk-1 T cells did not show any cytotoxic activity, indicating a correlation between the cytotoxic activity of clone bb1-2 T cells and their ability to elicit lichen planus-like lesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Cloned auto-Ia-reactive T cells elicit lichen planus-like lesion in the skin of syngeneic mice

To explore the physiologic or pathologic roles of autoreactive T cells, we examined immunological functions of several autoreactive mouse T cell clones in vitro and in vivo. All of the T cell clones were Lyt-2-, L3T4+ and showed self-I region-restricted proliferative responses (one clone was self-I-E restricted, the other clones were self-I-A restricted). One clone derived from C57BL/6 mouse and reactive to the self-I-Ab product (clone bb1-2) showed cross-reactivity to the I-Ak product. Among four such auto-Ia-reactive T cell clones examined, one clone produced fairly large amounts of interleukin 2 (IL 2) in response to syngeneic stimulator cells, and mediated help for the in vitro cytotoxic T cell (CTL) responses of syngeneic thymocytes, whereas this clone did not mediate in vitro antibody responses of syngeneic B cells. The other three clones were producers of small amounts of IL 2 and did not mediate the in vitro CTL responses. Among the three clones, clone bb1-2 showed strong regulatory function, and clone kk-1 (B10.BR origin and self-I-Ak reactive) showed weak regulatory function in vitro antibody responses of syngeneic B cells. The physiologic or pathologic roles of autoreactive T cells in vivo were explored by injecting subcutaneously clone kk-1 T cells or clone bb1-2 T cells into the footpads of the respective syngeneic mice. Clone kk-1 T cells injected into syngeneic mice elicited swelling of the footpad and marked accumulation of mononuclear cells in the dermis, leaving the epidermis intact, as in the delayed-type hypersensitivity reaction. As a notable finding, clone bb1-2 T cells injected into syngeneic mice elicited marked swelling of the footpad and lichen planus-like skin lesions, i.e., infiltration of lymphocytes in the epidermis and epidermal cell damage. The lymphocytes infiltrating in the epidermis were evaluated, as were the injected clone bb1-2 T cells expressing the Lyt-1.2 phenotype, by examination of the skin lesions elicited in C3H/He mice (H-2k, Lyt-1.1, 2.1) by the clone T cells. Clone bb1-2 T cells exerted in vitro cytotoxicity against H-2b and H-2k target cells, whereas clone kk-1 T cells did not show any cytotoxic activity, indicating a correlation between the cytotoxic activity of clone bb1-2 T cells and their ability to elicit lichen planus-like lesions.(ABSTRACT TRUNCATED AT 400 WORDS)

[A surgical case of submucosal esophageal carcinoma with esophageal leiomyoma misdiagnosed as esophageal]

A 56-year-old man with submucosal esophageal carcinoma combined with esophageal leiomyoma is presented. He had suffered from progressive dysphagia and vomiting. X-ray and endoscopic examination revealed severe stenosis of the lower esophagus with smooth mucosa, and CT scan demonstrated a circular and localized tumor. The histological diagnosis of esophageal leiomyoma was made by means of surgical biopsy. Resection of the lower esophagus and upper stomach was performed. But the postoperative pathological examination revealed submucosal esophageal squamous cell carcinoma combined with esophageal leiomyoma. The etiology and diagnosis in this case were discussed.

Lichenoid tissue reaction induced by local transfer of Ia-reactive T-cell clones

Epidermal basal cell damage in lichenoid tissue reactions (LTR) is considered to be the result of immunologic injury. In this study, we propose that LTR may be caused by local activation of Ia-reactive T cells. We have established allo-Iak-reactive helper T-cell clones and examined their behavior after adoptive transfer. We show that local transfer of 3 allo-Iak-reactive helper T-cell clones with different cross-reactivities and functions in vitro can cause delayed type hypersensitivity (DTH) reactions in vivo with antigen specificities identical to those demonstrated in vitro. Clone SK.1, when injected into appropriate recipients, caused massive dermal infiltrates of neutrophils and mononuclear cells. The latter were attracted to the epidermis and induced LTR-like basal cell degeneration which peaked at 72 h. Appropriate recipients were those strains of mice whose spleen cells were able to stimulate SK.1 cells to proliferate in vitro. Two other clones, SK.2.18 and SK.2.16, evoked significant DTH responses in their appropriate recipients, but the massive cellular infiltrates induced by either clone never invaded the epidermis or produced an LTR. The degeneration of epidermal cells caused by SK.1 cells did not correlate with the tested functions of this clone in vitro. The finding that only 1 of the 3 allo-Ia-reactive helper T-cell clones induced epidermotropic cellular infiltrates indicates that the infiltrative pattern of leukocytes in skin may depend on the particular T-cell clone that is activated.

Cloning and sequencing of cDNA of bovine N-acetylglucosamine (beta 1-4)galactosyltransferase

Galactosyltransferases constitute a family of enzymes, each member of which transfers galactose from UDPgalactose to a specific acceptor molecule, generating a specific galactose-acceptor linkage. Two synthetic oligonucleotides, 27mer and 21mer, were synthesized, based on the amino acid sequences of two peptides derived from bovine milk N-acetylglucosaminide (beta 1-4)galactosyltransferase (EC 2.4.1.90), and used as hybridization probes to isolate cDNA clones for galactosyltransferase from a bovine mammary gland cDNA library. One of the plasmids, designated pLbGT-1, contains an insert of about 3.7 kilobases that hybridizes to both of the probes and encodes the amino acid sequences of five peptides obtained from bovine milk (beta 1-4)galactosyltransferase. A second plasmid, designated pLbGT-2, contains an insert of about 4.1 kilobases that hybridizes to only the 27mer and that encodes a polypeptide containing the sequence of the carboxyl-terminal 120 residues identical to the peptide encoded by pLbGT-1; the rest of the protein sequence, however, does not contain known sequences from bovine galactosyltransferase. The two cDNAs contain a 3'-untranslated region of about 2.7 kilobases that includes two copies of the Alu-equivalent sequences. pLbGT-1 and pLbGT-2 hybridize to mRNAs of various sizes obtained from the bovine and rat mammary gland and the human mammary tumor cell line MCF-7, with the longest mRNA from each species being around 4.5 kilobases. The results show that pLbGT-1 is a cDNA clone for bovine (beta 1-4)galactosyltransferase, and pLbGT-2 encodes a protein that is structurally and may be functionally related to transferases.

[Immunohistological studies on the identification of T cells and T cell subsets infiltrating in human stomach cancer tissues]

T cells and T cell subsets in human gastric cancer tissues were identified using the immunoperoxidase technique with anti-T cell monoclonal antibodies (Leu-1, Leu-2, Leu-3 and Leu-4), anti-HLA-DR(Ia) monocronal antibody, and anti-Ig sera. The majority of lymphocytes infiltrating into gastric cancer tissues were Leu-1 and Leu-4 positive T cells; they consisted of a Leu-2 positive T cell subset (Tc/s) and a Leu-3 positive T cell subset (Th/i). Leu-2 positive T cells infiltrated the gastric cancer tissues of 6 patients with a moderate or marked degree of lymphocyte infiltration; Leu-3 positive T cells infiltrated these tissues of 11 patients. These results show that the degree of T cell and T cell subset infiltration may effect the host-tumor relationship.

Allo-Ia reactive murine T-cell lines. II. Mechanisms of clonal expansion of T cells explored by use of the allo-Ia reactive T cell clones

Murine T cell clones, which were retrieved from an A.TH anti-A.TL(lak) T cell line and had been long-term cultured in the medium supplemented with T cell growth factor (TCGF) and mitomycin C(MMC)-treated feeder cells of either Is or Ik haplotype, were found to survive in TCGF-free medium for a long time, quite in contrast to so far reported TCGF-dependent T cell clones. When T cells of these clones at the full growth in the TCGF-medium were transferred to TCGF-free medium, they survived at resting state for a long time, and half-life, i.e., the time when 50% of the transferred cells were still viable, of some clones reached 20 days. The cloned T cells at the resting state retained full responsiveness to the specific lak antigen but lost the responsiveness to TCGF as determined by [3H]thymidine uptake, whereas the same T cells harvested from TCGF-medium did not show the antigen-specific responsiveness. The cloned T cells at the resting state showed marked DNA synthesis in response to the specific antigen but never entered the phase of the cell division. Addition of TCGF to the antigen-activated cloned T cells at their peak DNA synthesis triggered the cell division without time lag. Thus, it was confirmed at a single clone level that two sequential signals, one via the antigen-receptor reacting with specific antigen and another via the TCGF-receptor accepting TCGF, are required for clonal expansion of T cells reacting with antigen. The mitogen-responsiveness among five clones was examined at their resting state; two clones responded to Con A and PHA only in the presence of accessory cells (MMC-treated, T cell-depleted syngeneic spleen cells), and one clone responded well to Con A and PHA in the absence of accessory cells. Thus, most of our clones retained physiologic characteristics of T cells directly collected from mice even after long-term culture in TCGF-medium.

Allo-Ia reactive murine T-cell lines. II. Mechanisms of clonal expansion of T cells explored by use of the allo-Ia reactive T cell clones

Murine T cell clones, which were retrieved from an A.TH anti-A.TL(lak) T cell line and had been long-term cultured in the medium supplemented with T cell growth factor (TCGF) and mitomycin C(MMC)-treated feeder cells of either Is or Ik haplotype, were found to survive in TCGF-free medium for a long time, quite in contrast to so far reported TCGF-dependent T cell clones. When T cells of these clones at the full growth in the TCGF-medium were transferred to TCGF-free medium, they survived at resting state for a long time, and half-life, i.e., the time when 50% of the transferred cells were still viable, of some clones reached 20 days. The cloned T cells at the resting state retained full responsiveness to the specific lak antigen but lost the responsiveness to TCGF as determined by [3H]thymidine uptake, whereas the same T cells harvested from TCGF-medium did not show the antigen-specific responsiveness. The cloned T cells at the resting state showed marked DNA synthesis in response to the specific antigen but never entered the phase of the cell division. Addition of TCGF to the antigen-activated cloned T cells at their peak DNA synthesis triggered the cell division without time lag. Thus, it was confirmed at a single clone level that two sequential signals, one via the antigen-receptor reacting with specific antigen and another via the TCGF-receptor accepting TCGF, are required for clonal expansion of T cells reacting with antigen. The mitogen-responsiveness among five clones was examined at their resting state; two clones responded to Con A and PHA only in the presence of accessory cells (MMC-treated, T cell-depleted syngeneic spleen cells), and one clone responded well to Con A and PHA in the absence of accessory cells. Thus, most of our clones retained physiologic characteristics of T cells directly collected from mice even after long-term culture in TCGF-medium.

Murine T cell lines that help induction and generation of allospecific cytotoxic T cells from thymocytes

Murine T cell lines that help induction and generation of allospecific cytotoxic T cells (CTL) from thymocytes cultured together with allogeneic stimulator cells have been established. It was done by successively culturing T cell blasts obtained from mixed lymphocyte cultures (MLC) in the medium supplemented with T cell growth factor (TCGF). The helper function of the long-term cultured T cells was antigen specific, radiation resistant, and not H-2 restricted. The helper function has been retained for more than 8 mo by the cells continually proliferating in the TCGF-supplemented medium. The T stimulated responsiveness of thymocytes to T cell mitogens. CTL activity seen in the original MLC waned rapidly during successive culture of this T cell line in TCGF medium T cell blasts from MLC successively cultured in continual presence of TCGF and the stimulator alloantigens retained strong CTL activity against the allogeneic stimulator cells for about 3 mo. All these T cell lines proliferating in TCGF medium expressed Thy 1 antigen and showed the appearance of a large T cell blast. These T cell lines could not proliferate in the absence of TCGF and lost responsiveness to T cell mitogens intrinsically.

Murine T cell lines that help induction and generation of allospecific cytotoxic T cells from thymocytes

Murine T cell lines that help induction and generation of allospecific cytotoxic T cells (CTL) from thymocytes cultured together with allogeneic stimulator cells have been established. It was done by successively culturing T cell blasts obtained from mixed lymphocyte cultures (MLC) in the medium supplemented with T cell growth factor (TCGF). The helper function of the long-term cultured T cells was antigen specific, radiation resistant, and not H-2 restricted. The helper function has been retained for more than 8 mo by the cells continually proliferating in the TCGF-supplemented medium. The T stimulated responsiveness of thymocytes to T cell mitogens. CTL activity seen in the original MLC waned rapidly during successive culture of this T cell line in TCGF medium T cell blasts from MLC successively cultured in continual presence of TCGF and the stimulator alloantigens retained strong CTL activity against the allogeneic stimulator cells for about 3 mo. All these T cell lines proliferating in TCGF medium expressed Thy 1 antigen and showed the appearance of a large T cell blast. These T cell lines could not proliferate in the absence of TCGF and lost responsiveness to T cell mitogens intrinsically.

Mechanisms of the adjuvant effect of nystatin on in vitro antibody response of mouse spleen cells: indication of nystatin as a B-cell mitogen and as a stimulant for polyclonal antibody synthesis in B cells

Adjuvanticity of nystatin, one of the polyenic antifungal antibiotics having as its primary target the membrane sterol of eukaryotic cells, was investigated by examining its effect on several functions of mouse spleen cells relevant to immunological phenomena in vitro. Nystatin was found to stimulate significantly DNA synthesis in thymus-independent (B) cells but not in thymus-dependent (T) cells. Like the other B-cell mitogens such as bacterial lipopolysaccharide (LPS), nystatin elicited nonspecifically polyclonal antibody synthesis in mouse spleen cell cultures, and also restored antibody response of T cell-deficient spleen cells of congenitally athymic nude mice to heterologous erythrocytes (RBC; thymus-dependent antigen). Thus, nystatin and LPS appeared to cause similar changes in the functions of spleen cells relevant to immunological events. However, antagonism but no additive effect in the adjuvanticity was revealed between the two adjuvants. As an interesting finding, the polyclonal generation of anti-RBC antibody-forming cells (AFC) in the spleen cell cultures by stimulation with B-cell mitogen, i.e., either nystatin or LPS, was not inhibited at all by inclusion of any anti-RBC antiserum, whereas, as is well known, the generation of AFC by stimulation with the antigen was specifically suppressed by the corresponding antiserum, indicating a difference in the genesis between the mitogen-induced AFC and the antigen-induced AFC.