Induction of autoantibody responses to GM-CSF by hyperimmunization with an Id-GM-CSF fusion protein

Fusion proteins consisting of an Ig containing xenogenic constant regions and granulocyte-macrophage colony stimulating factor (Id-GM-CSF) are potent immunogens capable of inducing anti-idiotypic Abs after two immunizations, without the usual need for adjuvants or carrier proteins. In this study, we investigated the effects of hyperimmunization with Id-GM-CSF and found that it induces anti-GM-CSF Abs that could bind to GM-CSF and neutralize its bioactivity in vitro. However, no detrimental effects of the anti-GM-CSF activity were apparent on the general health of the animals or on their base line white blood cell counts. Mice with the anti-GM-CSF activity reconstituted their peripheral white blood cells with identical kinetics as control mice after high dose cyclophosphamide treatment, sublethal irradiation, or lethal irradiation followed by syngeneic bone marrow transplantation. Primary and secondary Ab responses to a variety of protein Ags, including an unrelated Ig Id, were not affected. However, the anti-Id response induced by an unrelated GM-CSF fusion protein that is dependent upon the GM-CSF bioactivity was impaired. To avoid any potential problems associated with inducing anti-GM-CSF Abs, we show that priming with the Id-GM-CSF protein and boosting with the Id protein alone were sufficient to induce comparable anti-Id titers without inducing anti-GM-CSF Abs. We conclude that although hyperimmunization of mice with the GM-CSF fusion protein induced neutralizing anti-GM-CSF Abs, this was of little consequence to the animals. Nevertheless, we have devised a strategy to overcome this potential limitation on the use of GM-CSF fusion proteins for immunization.

Induction of autoantibody responses to GM-CSF by hyperimmunization with an Id-GM-CSF fusion protein

Fusion proteins consisting of an Ig containing xenogenic constant regions and granulocyte-macrophage colony stimulating factor (Id-GM-CSF) are potent immunogens capable of inducing anti-idiotypic Abs after two immunizations, without the usual need for adjuvants or carrier proteins. In this study, we investigated the effects of hyperimmunization with Id-GM-CSF and found that it induces anti-GM-CSF Abs that could bind to GM-CSF and neutralize its bioactivity in vitro. However, no detrimental effects of the anti-GM-CSF activity were apparent on the general health of the animals or on their base line white blood cell counts. Mice with the anti-GM-CSF activity reconstituted their peripheral white blood cells with identical kinetics as control mice after high dose cyclophosphamide treatment, sublethal irradiation, or lethal irradiation followed by syngeneic bone marrow transplantation. Primary and secondary Ab responses to a variety of protein Ags, including an unrelated Ig Id, were not affected. However, the anti-Id response induced by an unrelated GM-CSF fusion protein that is dependent upon the GM-CSF bioactivity was impaired. To avoid any potential problems associated with inducing anti-GM-CSF Abs, we show that priming with the Id-GM-CSF protein and boosting with the Id protein alone were sufficient to induce comparable anti-Id titers without inducing anti-GM-CSF Abs. We conclude that although hyperimmunization of mice with the GM-CSF fusion protein induced neutralizing anti-GM-CSF Abs, this was of little consequence to the animals. Nevertheless, we have devised a strategy to overcome this potential limitation on the use of GM-CSF fusion proteins for immunization.

Molecular cloning and characterization of a novel gonadotropin-releasing hormone from the gilthead seabream (Sparus aurata)

A novel form of gonadotropin-releasing hormone (GnRH) had been recently isolated and characterized from the gilthead seabream (Sparus aurata). This novel form, designated sbGnRH, was suggested to be the endogenous stimulator of gonadotropin release. This paper reports on the isolation and characterization of a 360-bp cDNA encoding the complete sbGnRH precursor. This precursor is composed of a 25 amino acid leader sequence, the biologically active sbGnRH, the cleavage site (Gly-Lys-Arg), and a 57 amino acid associated peptide (GAP). Comparison of the nucleotide and amino acid sequence of the sbGnRH precursor with precursors of other GnRH forms places the sbGnRH precursor evolutionarily closer to the mammalian GnRH and chicken GnRH-I, which have also been shown to be the relevant forms for gonadotropin release in mammals and birds, respectively. The characterization of the sbGnRH precursor cDNA lays the foundation for future studies aimed toward understanding the neuroendocrine control of reproduction in seabream and other fish species.

Production of a biologically active recombinant teleostean growth hormone in E. coli cells

We have isolated and characterized several recombinant lambda phage clones carrying growth hormone (GH) cDNA of striped bass (Morone saxatilis). Nucleotide sequence and the predicted amino acid sequence of sbGH was determined from a recombinant clone carrying the longest cDNA insert. The sbGH cDNA encodes a pre-hormone of 204 amino acid residues. Comparison of the predicted amino acid sequence of sbGH with those of other vertebrates revealed different degrees of sequence identity: approximately 98% with European sea bass; 90% with bluefin tuna; bonito and red seabream; 71% with winter flounder; 64% with salmonids; 55% with carp; and 38% with human. Expression of the mature sbGH cDNA (without the signal peptide sequence) in E. coli cells under regulation of the lambda phage PL promoter produced a polypeptide of 20 kDa. Following renaturation, this recombinant hormone was shown to be biologically active in a radioreceptor competition binding assay and in the induction of hepatic insulin-like growth factor I (IGF-I) mRNA synthesis in vivo.

Idiotype-cytokine fusion proteins as cancer vaccines. Relative efficacy of IL-2, IL-4, and granulocyte-macrophage colony-stimulating factor

Idiotypic determinants, antigenic sites expressed on the variable region of Ig molecules of malignant B cells, represent tumor-specific Ags but are weak immunogens. We have previously shown that the immunogenicity can be dramatically increased by fusing tumor Id to granulocyte macrophage (GM)-CSF. Here, we demonstrate that fusion proteins with IL-2 or IL-4 can also be highly immunogenic. Co-immunization of these fusion proteins with another Id demonstrated the importance of physical linkage between the cytokine and relevant Ag for this enhancement. All three fusion proteins are capable of eliciting significant levels of specific Abs against the Id without the use of carrier proteins or adjuvants, although the GM-CSF fusion protein appeared to be unique in its ability to induce higher titers of anti-Id Abs in the primary response. Furthermore, the Id-IL-2 fusion protein induced high titers of IgG2a and IgG3 anti-Id Abs, whereas the Id-IL-4 and Id-GM-CSF fusion proteins did not. Despite the differences, tumor protection was comparable in all mice having significant titers of anti-Id Abs, regardless of the fusion protein used. We concluded that Id-cytokine fusion proteins are potent immunogens that can elicit significant antitumor immunity. The general approach of fusing a cytokine to a potential Ag may be applicable to the design of vaccines for immunotherapy of other types of tumors as well as for other pathogens and disease states.

Idiotype-cytokine fusion proteins as cancer vaccines. Relative efficacy of IL-2, IL-4, and granulocyte-macrophage colony-stimulating factor

Idiotypic determinants, antigenic sites expressed on the variable region of Ig molecules of malignant B cells, represent tumor-specific Ags but are weak immunogens. We have previously shown that the immunogenicity can be dramatically increased by fusing tumor Id to granulocyte macrophage (GM)-CSF. Here, we demonstrate that fusion proteins with IL-2 or IL-4 can also be highly immunogenic. Co-immunization of these fusion proteins with another Id demonstrated the importance of physical linkage between the cytokine and relevant Ag for this enhancement. All three fusion proteins are capable of eliciting significant levels of specific Abs against the Id without the use of carrier proteins or adjuvants, although the GM-CSF fusion protein appeared to be unique in its ability to induce higher titers of anti-Id Abs in the primary response. Furthermore, the Id-IL-2 fusion protein induced high titers of IgG2a and IgG3 anti-Id Abs, whereas the Id-IL-4 and Id-GM-CSF fusion proteins did not. Despite the differences, tumor protection was comparable in all mice having significant titers of anti-Id Abs, regardless of the fusion protein used. We concluded that Id-cytokine fusion proteins are potent immunogens that can elicit significant antitumor immunity. The general approach of fusing a cytokine to a potential Ag may be applicable to the design of vaccines for immunotherapy of other types of tumors as well as for other pathogens and disease states.

Functional importance of an Sp1- and an NFkB-related nuclear protein in a keratinocyte-specific promoter of rabbit K3 keratin gene

We have shown previously that a 300-base pair (bp) 5' upstream sequence of rabbit keratin K3 gene (RK3) can function as a keratinocyte-specific promoter in transient transfection assays. Electrophoretic mobility shift assays using various overlapping and mutated oligonucleotides established that corneal keratinocyte nuclear proteins bound in vitro to two sites (B and E). Immunosupershift and UV cross-linking established that the keratinocyte nuclear binding protein of site B (5'-GGGGCTTTCC-3', -262 to -253 bp) was NFkB consisting of the p65 and p50 subunits. The E site contained an unusual GC-rich motif (5'-CCGCCCCCTG-3', -203 to -194 bp) whose sequence deviated from the Sp1 consensus in 4 out of 10 positions; this site bound an Sp 1-related keratinocyte nuclear protein. Mutagenesis of the NFkB, GC motif, and both sites abolished 20, 50, and 75%, respectively, of the promoter activity in transfected keratinocytes. The NFkB-like keratinocyte nuclear protein was barely detectable in kidney epithelial cells, HeLa, and fibroblasts. The Sp1-related nuclear protein was abundant in keratinocytes and simple epithelial cells, but was much less abundant in fibroblasts. These results indicate that NFkB is present in significant quantities in keratinocyte nuclei and that the tissue restriction of the NFkB- and Sp1-related proteins, in combination with other factors, may contribute to the keratinocyte specificity of RK3 promoter.

Interferon-gamma (IFN-gamma) and interleukin-6 (IL-6) in peritoneal fluid and macrophage-conditioned media of women with endometriosis

PROBLEM

The presence of the various cytokines in human peritoneal fluid has been incompletely evaluated. Changes in cytokine levels may be related to activation of peritoneal macrophages, development of endometriosis, and infertility. This study assesses peritoneal fluid levels of interferon gamma (IFN-gamma) and interleukin-6 (IL-6), and peritoneal macrophage production of IL-6, in women with and without endometriosis.

METHOD

Peritoneal fluid was obtained from 62 women at the time of diagnostic or operative laparoscopic surgery for benign gynecologic disease. Peritoneal macrophages were isolated, cultured for 24 h, and the culture media collected. IFN-gamma and IL-6 levels in peritoneal fluid samples and macrophage conditioned media were determined by commercial ELISA.

RESULTS

IL-6 was significantly higher in the macrophage conditioned media of women with endometriosis as compared with controls. IL-6 levels were fourfold higher in early stage endometriosis (P < 0.05) and eightfold higher in advanced endometriosis. There were no significant differences between groups in the peritoneal fluid levels of IL-6 or IFN-gamma.

CONCLUSIONS

Peritoneal macrophage IL-6 secretion is increased in women with endometriosis, and appears to correlate with disease stage. IFN-gamma does not appear to be responsible for the activation of macrophages in women with endometriosis.

A comparison of two phase I trial designs

Phase I cancer chemotherapy trials are designed to determine rapidly the maximum tolerated dose of a new agent for further study. A recently proposed Bayesian method, the continual reassessment method, has been suggested to offer an improvement over the standard design of such trials. We find the previous comparisons did not completely address the relative performance of the designs as they would be used in practice. Our results indicate that with the continual reassessment method, more patients will be treated at very high doses and the trials will take longer to complete. We offer some suggested improvements to both the standard design and the Bayesian method.

The inhibitory action of taxol on granulosa cell steroidogenesis is reversible

Taxol is a novel anticancer agent extracted from the bark of Pacific yew trees. The drug has been approved by the FDA for the treatment of advanced ovarian cancer and is in clinical trials for other malignancies, including breast cancer. The goals of this study were to determine whether taxol adversely and irreversibly affects ovarian granulosa cell steroidogenesis. Cultured porcine granulosa cells were treated with taxol (0.12-12 microM) or vehicle (0.01-1% ethanol) in the absence or presence of 10(-9) M hCG in a time- and dose-response study. Morphological changes were recorded every 2 h, and media were collected for the measurement of progesterone (P4) and 17 beta-estradiol. Taxol suppressed both basal P4 and 17 beta-estradiol production and hCG-stimulated P4 production in a time- and dose-dependent manner and drastically changed cell shape by causing disorganization of microtubule bundles and other subcellular organelles. hCG partially reversed the steroid inhibition induced by taxol. These changes are not attributed to ethanol used as the vehicle, because ethanol at higher concentrations than that present in taxol did not suppress P4 production. When taxol was removed from the culture, P4 production returned to control levels. The results of this study show that taxol causes a significant, but reversible, inhibition of granulosa cell steroidogenesis. This inhibitory effect can be partially overcome by co-treatment with hCG.

Two unique CYP1 genes are expressed in response to 3-methylcholanthrene treatment in rainbow trout

In animals, exposure to polyaromatic hydrocarbons (PAHs) such as 3-methylcholanthrene (3-MC) is known to induce the expression of two unique cytochrome P450 genes, CYP1A1 and CYP1A2. These genes are thought to have originated by a gene duplication event and diverged no more than 250 million years ago (D. W. Nerbert and F. J. Gonzalez, 1987, Annu. Rev. Biochem. 56, 945-993). Lower vertebrates, such as fish, diverged from land animals before this time and are thought to express only a single CYP1 gene. In this paper, we present evidence to refute this hypothesis and report the isolation and complete genomic nucleotide sequence of two distinct CYP1 genes in rainbow trout. Genomic clones encoding the entire CYP1A1 and CYP1A2 genes were characterized. DNA sequence analysis revealed that both genes contained seven exons and six introns. Exons 1-7 of CYP1A1 and CYP1A2 were highly similar in length and nucleotide sequence. In contrast, the 5'-flanking region and introns 1, 2, 5, and 6 of both genes were significantly less conserved. Two xenobiotic regulatory elements (XREs) were identified in the 5'-flanking region of CYP1A1 but not in that of CYP1A2. The 5'-most start site of transcription was determined to begin at a cytosine residue 27 bases downstream of the putative TATA box of both genes. Northern blot analysis demonstrated that exposure to 3-MC resulted in an increase in CYP1 mRNA levels in the liver. RNase protection assays conducted with riboprobes specific for either CYP1A1 or CYP1A2 confirmed that the transcripts of both genes were expressed in rainbow trout liver in response to 3-MC treatment.

Extension of one-sided test to multiple treatment trials

In a two-treatment clinical trial, a one-sided test is sometimes used in reaching a decision. Usually we are interested in doing a one-sided test because of the existence of an unequal preference between the two treatments. When a standard control is just as good or better than the new experimental treatment (which has more toxicity or cost), we will stay with the standard control. In this paper, we extend the concept of a one-sided test to the multiple treatment trial where three or more treatments are involved. We assume that there is an order of strictly decreasing preference among the treatments. We propose two multiple-step decision procedures that are similar to the bubble sorting algorithm and will guarantee a high probability of finally selecting the correct treatment. We also provide methods to calculate the sample size required to detect a specific difference. The derivation is based on normal data, and the extension to binomial or exponential data with random censoring is through large sample approximation.

A multiple decision procedure in clinical trials

In some multiple treatment arm clinical trials there is an order of preference for the treatments based on secondary considerations like toxicity or cost. In this paper, we consider the case where two or more treatments could have equal prior preference. This formulation includes the problem of comparing several equally preferred experimental treatments to one control, or the comparison of a combination with its components. Our decision procedures will guarantee a high selection probability for the correct treatment(s) when that selection is appropriate. We establish sample size requirements for our decision procedures which can be applied to clinical trials with normal, binomial, or right censored exponential endpoints.

Age-related and tissue-specific levels of five forms of insulin-like growth factor mRNA in a teleost

A reverse transcriptase/PCR assay was employed to amplify an internal portion of insulin-like growth factor I (IGF I) and IGF II cDNA from the RNA of juvenile rainbow trout (Oncorhynchus mykiss) in an effort to detect analogues to the multiple size forms of IGF mRNA known to exist in mammals. After cloning and sequencing the PCR products, 4 variant size forms of trout IGF I mRNA and 1 form of IGF II mRNA were evident. The full cDNA nucleotide sequence of 1 form of IGF I mRNA and IGF II mRNA have been previously reported; the full cDNA nucleotide sequence of a second form of IGF I mRNA and PCR-derived nucleotide sequences of the 2 additional IGF I mRNA forms are reported herein. We define the 4 forms of IGF I mRNA (IGF IEa-1, Ea-2, Ea-3, and Ea-4) as having E-domain peptide lengths of 35, 47, 62, and 74 predicted amino acid residues, respectively. RNAse protection assays were used to quantify the mRNA levels of each of the 5 IGFs in 8 tissues of both juvenile and adult trout, as well as in testes and ovaries of adult trout. The IGF mRNA levels, normalized with 18S rRNA levels, suggest (1) at least 1 form of IGF I and IGF II mRNA are present at both developmental stages in all tissues examined; (2) all 5 IGF mRNA forms are present at their highest levels in the liver (p < 0.05); and (3) adults have significantly higher IGF mRNA levels than juveniles in the liver (p = 0.0047).

A multiple-step selection procedure with sequential protection of preferred treatments

Dunnett (1955, Journal of the American Statistical Association 50, 1096-1121) proposed a one-step many-one test to compare several experimental treatment means with a control. However, after the control treatment is rejected, one would want to make comparisons among the experimental treatments. We assume that there is an order of decreasing preference among the experimental treatments based on other considerations. We propose in this paper a multiple-step selection procedure, an extension of Dunnett's one-step many-one test that will give protection to the preferred treatments and guarantee a high selection probability of the correct treatment when that selection is appropriate. We also provide methods to calculate the sample size required to carry out this test for normal, binomial, and exponential data with random censoring.

Structure of the channel catfish (Ictalurus punctatus) growth hormone gene and its evolutionary implications

A DNA fragment of 1.6 kilo base pairs (kb), encoding part of the channel catfish (Ictalurus punctatus) growth hormone (GH) gene, was generated by the polymerase chain reaction (PCR) using 2 degenerate synthetic oligonucleotides (30 and 33 mer) derived from the N- and C-terminal amino acid sequences of the catfish GH polypeptide as amplification primers and with catfish genomic DNA as a template. This DNA fragment was used as a probe for the isolation of a catfish GH gene from a genomic library constructed in a lambda phage cloning vector, lambda Dash II. Three positive clones were isolated, and their complete nucleotide sequences were determined. Nucleotide sequences from clones 1 and 3 were identical, whereas clone 2 had 2 base substitutions. The gene spans approximately 3 kb and is comprised of 5 exons and 4 introns. The initiation codon, the termination codon, and the canonical polyadenylation sequence were identified. The amino acid sequence deduced from the predicted coding region of the gene is in agreement with that of the native GH polypeptide sequence. A sequence (TATAAAA) matching the TATA box consensus sequence was located at nucleotide positions -30 to -23. Furthermore, 2 sequences corresponding to the mammalian Pit-1/GHF-1 binding sites (consensus sequence TT[AA]TATNCAT) were identified in the 5' flanking region starting at positions -113 and -134. Another sequence (GTACCAGTGA) conserved among the GH genes of the channel catfish and other known animal species was also identified at position -220. The biological functions of this sequence remain to be determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular localization of luteinizing hormone receptor immunoreactivity in the ovaries of immature, gonadotropin-primed and normal cycling rats

In this study we used two monoclonal antibodies against purified LH receptor (LHR) to localize and quantify LHR in ovarian compartments during follicular development, using gonads from immature, gonadotropin-primed, and normal cycling rats. In early preantral follicles, LHR immunoreactivity (LHRI) was identified in vascular endothelium and subsequently appeared in vascular pericytes. In healthy small antral (200-550-microns) follicles, LHRI continued to be present in thecal pericytes, but not in cells of the theca interna. However, in small antral follicles undergoing atresia, a dramatic decrease in thecal vessel LHRI with a concomitant increase in LHRI in hypertrophied theca was observed. In healthy antral follicles, LHRI of thecal cells was not observed until the cells reached medium (550-microns) size. High LHRI was occasionally observed in macrophage-like cells adjacent to the oocyte of large preantral follicles and among granulosa layers of medium-sized antral follicles. In the membrana granulosa, LHRI first appeared in cumulus cells of medium-sized antral follicles and subsequently spread to the entire granulosa cell population of large (750 microns) antral follicles. Treatment of immature rats with eCG markedly enhanced LHRI in theca and granulosa cells of all antral follicles, while eCG/hCG-treated (pseudopregnant) rats showed lack of LHRI in follicles and interstitial glands, but not in corpora lutea (CL). Within degenerating CL in the cycling ovary, compared to fresh and mature CL, a significant decrease occurred in intracellular LHRI. Our observations indicate that 1) vascular pericytes may play a role in follicular development; 2) LHR expression in granulosa may require an interaction of macrophages, oocytes, and cumulus cells; and 3) thecal hypertrophy accompanied by enhanced LHR expression occurs on follicles undergoing atresia.

Molecular cloning and expression of yellowfin porgy (Acanthopagrus latus houttuyn) growth hormone cDNA

1. The growth hormone cDNA of yellowfin porgy (ypGH cDNA) consisted of 915 base pairs. 2. The deduced amino acid (aa) sequence showed that the pre-GH comprised 204 residues, of which the first 17 residues formed a signal peptide. 3. Comparison of aa sequence of ypGH to seabream, tuna, rainbow trout and chum salmon showed that ypGH shared 95.1, 94.1, 65.3 and 62.4% homology with these species, respectively. 4. By expressing the ypGH cDNA in E. coli, a polypeptide around 23 kilodaltons (kDa) was found which was immunoreactive to GH antibody.

Expression and inheritance of RSVLTR-rtGH1 complementary DNA in the transgenic common carp, Cyprinus carpio

Transgenic common carp, Cyprinus carpio, possessing the long terminal repeat (LTR) sequence of avian Rous sarcoma virus (RSV) fused to the rainbow trout (rt) growth hormone (GH1) complementary DNA (cDNA) were produced by microinjection. Initial studies showed that the transgenic common carp transmitted the foreign DNA to a significant fraction of their progeny in three of four crosses of transgenic males with control females. These progeny grew 20 to 40% faster than their nontransgenic full siblings. In this study, additional experiments were conducted to evaluate inheritance and expression of the foreign GH gene in transgenic common carp, and the growth performance of these transgenic fish. Four P1 (parental generation produced by microinjection) x nontransgenic controls, four P1 x P1, and one P1 x F1 matings of transgenic carp containing RSVLTR-rtGH1 cDNA were made. The percentages of transgenic progeny resulting from these matings were: 0, 32, 42, 100 (4 progeny only), 21, 21, 31, 30, and 23%, respectively. All crosses except 1 siblot (control x P1) exhibited progeny ratios below the expected 50 or 75% transgenic. These results indicate that most of these transgenic P1 had the foreign gene in their germ line but were mosaics, and at least one transgenic individual did not have the RSVLTR-rtGH1 cDNA in the gonadal tissue. Both P1 and F1 transgenic fish produce trout growth hormone mRNA and polypeptide as determined by reverse transcription polymerase chain reaction amplification, RNA dot-blot hybridization, and radio-immunobinding assay. Growth response by families of F1 transgenic fish to the addition of rtGH1 cDNA varied widely.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of a second insulin-like growth factor in a fish species

An internal portion of insulin-like growth factor (IGF) amplified from the total cDNA of rainbow trout (Oncorhynchus mykiss) liver by a PCR was used to screen a rainbow trout liver cDNA library, and recombinant clones encoding two distinct IGFs were isolated. On the basis of a 98.7% nucleotide and 98.3% predicted amino acid identity to coho salmon IGF-I, one cDNA sequence was identified as rainbow trout preproinsulin-like growth factor I (rtIGF-I). The second cDNA sequence shared 46.1% and 43.3% identity with rtIGF-I at the nucleotide and predicted amino acid levels, respectively, and was identified as rainbow trout preproinsulin-like growth factor II (rtIGF-II). Predicted amino acid sequence comparisons of rtIGFs with those of human IGFs indicate that rtIGF-I is more similar to human IGF-I than to human IGF-II, and that rtIGF-II is more similar to human IGF-II than to human IGF-I. Southern blot analysis of rainbow trout genomic DNA probed with rtIGF-I and -II cDNA suggests that these two forms of IGF originate from separate genes. The presence of a teleost IGF-II suggests that the divergence of IGFs occurred early in vertebrate evolution.

Antigen selection in human lymphomagenesis

Although surface immunoglobulin plays a central role in the differentiation and growth of normal B-cells, its role in the growth of human B-cell malignancies is largely a matter of conjecture. Human follicular lymphomas are attractive systems to study in part because they are clones of cells sharing many similarities with germinal center B-cells which are critically dependent on antigen selection for survival. Nucleotide sequence information was determined for the immunoglobulin heavy chain variable genes expressed by two cases of follicular lymphoma. In addition, the germ line variable gene counterparts were also cloned and sequenced from biopsy material obtained from both of these patients. Numerous mutations from germ line were present in the variable genes from both of these cases, many of which accumulated during expansion and growth of these lymphomas. Moreover, the mutations that accumulated during tumor expansion were distributed in a manner that almost certainly was dependent on positive selection presumably mediated by contact with an antigen. These data indicate that antigen selection is probably important for the growth and clonal evolution of follicular lymphomas.

Clonal expansion in follicular lymphoma occurs subsequent to antigenic selection

The genesis of human follicular lymphoma (FL) is a multistep process. The initial event is thought to be the chromosomal translocation t(14;18)(q32;q21) juxtaposing the bcl-2 proto-oncogene with the immunoglobulin (Ig) H chain locus joining segment (JH) as an error of D-J or V-D joining in the pre-B cell. However, FL is recognized clinically as a tumor of surface Ig (sIg)-positive B cells with morphologic and phenotypic similarities to the centrocyte of the secondary immune response. Thus, additional steps must be involved in the clonal expansion of the FL tumor cell beyond the activation of bcl-2 as a consequence of the t(14;18) translocation. Like the normal centrocyte, somatic mutations accumulate in the variable (V) genes of FL tumor B cells. To determine if clonal expansion of FL occurs before or after the development of the malignant follicle, we sought to examine the evolution of the FL V gene from its unmutated germline (GL) counterpart. To obtain the GL gene we first cloned the productively rearranged V gene of patient MT FL and obtained the clone rMTF. A hybridization probe derived from the 2.1-kb region upstream of the V gene in clone rMTF identified a single band in Southern blot hybridization of GL DNA. This probe was used to screen a size-selected library, and candidate GL V genes were isolated. Two identical clones, MTGL1 and 2, proved to have upstream regions (USRs) that were colinear with the USR of the rMTF. Thus, the MTGL clones represent the unmutated GL V genes, which were productively rearranged in the MT FL. Comparison of the GL V gene sequence to a consensus of MT FL V gene sequences revealed 42 mutations, demonstrating that malignant clonal expansion occurred subsequent to the activation of somatic mutation, presumably in the malignant follicle. Furthermore, the individual FL V gene sequences segregated into two distinct patterns of mutation. The major population represented 71% of the clones, and the minor population 29%. To investigate possible mechanisms for the parallel selection of distinct tumor cell populations, we analyzed the pattern of silent and replacement mutations within the V gene sequences. We found that in the framework regions (FRs) of both populations there were significantly fewer replacement changes than expected, suggesting that negative selective pressure was maintaining the structural integrity of the sIg. In contrast, the complementarity determining regions (CDRs), which make up the antigen binding domain of Ig, had an excess of replacement changes, suggesting positive selection for altered ligand binding.

Radial keratotomy: eleven-year experiences

During the period from 1980 to 1991, Radial Keratotomy (RK) had been done by the author under topical anesthesia in more than 10,000 cases, mostly on both eyes at the same time. Those patients had myopia with a preoperative refractive error between 1.5 and 20.0 diopters (D). The surgical technique consisted of 4, 8, 16 incisions using a diamond knife with micrometer and the diameter of the central clear zone was mostly 3.0 mm and determined by preoperative refractive error. Many different procedures were tried to improve the effect of RK, including redeepening intentional microperforations at 1.5 mm, 3 mm, 5 mm distance from the corneal center. But these procedures had no significant effect 6 months after the operation. Complications such as infection, glaucoma, cataract, etc. were almost none. Results of RK on long term follow up showed hyperoptic tendency, and the visual fluctuation were none or minimal.

Transfer, expression, and inheritance of salmonid growth hormone genes in channel catfish, Ictalurus punctatus, and effects on performance traits

We examined expression and inheritance of salmonid growth hormone genes RSVLTR-rtGH1 cDNA and RSVLTR-csGH cDNA, transferred to channel catfish (Ictalurus punctatus) by microinjection. One to 9 copies of the foreign DNA were inserted in either head-to-tail tandem array at single insertion sites or single copies at multiple insertion sites. All P1 transgenic catfish evaluated produced salmonid growth hormone regardless of the construct. Five P1 x P1 matings were accomplished. The spawning rate and fertility of these P1 transgenics in artificial spawning conditions were comparable to those of normal channel catfish. In two of three years, 100% spawning and 100% hatch were obtained. Percent transgenic progeny observed in the five matings were 20, 52, 7, 47, and 0%, which was lower (P < 0.001, chi 2) than the 75% inheritance expected assuming the P1 brood stock had at least one copy of the foreign gene integrated and were not mosaics in the germ line. At least 7 of 10 P1 were mosaics, and a minimum of 2 of 10 P1 did not possess the salmonid growth hormone genes in their germ line. P1 transgenics grew at the same rate as their nontransgenic full siblings, which is not surprising because the P1 were mosaics. F1 transgenic progeny in two families possessing RSVLTR-csGH cDNA grew 26% faster, to 40 to 50 gm, than their nontransgenic full siblings when evaluated communally. One F1 progeny group produced by RSVLTR-rtGH1 cDNA x RSVLTR-csGH cDNA mating and one F1 progeny group (parents either RSVLTR-rtGH1 cDNA or RSVLTR-csGH cDNA) grew at the same rate as normal full siblings when grown communally to 25 gm and 60 mg, respectively. In families where F1 progeny grew faster than controls, the range in body weight and coefficient of variation for the transgenic full siblings were less than those for controls. In families where F1 progeny grew at the same rate as controls, range in body weight and coefficient of variation were similar for transgenic and normal individuals. The percent deformities observed in P1 transgenics (13.6%) was higher (P < 0.05) than in microinjected P1 nontransgenics (5.1%). Percent deformities in transgenics and control F1 channel catfish was not different (p > 0.05; 0.5 and 2.8%, respectively).