Imaging findings of lipomas in the orofacial region with CT, US, and MRI

OBJECTIVE

The aim of this study was to document retrospectively the imaging findings of lipomas with the use of computed tomography, ultrasonography, and magnetic resonance imaging.

STUDY DESIGN

Thirteen patients with 11 lipomas and 2 lipomatoses were evaluated. Eleven cases were examined by computed tomography, 9 by ultrasonography, and 3 by magnetic resonance imaging.

RESULTS

Lipomas had a density ranging from -134 to -83 Hounsfield units, (mean-108) on the computed tomography images. The margins were ill defined in 9 of 10 cases. The superficial muscles were displaced externally in 8 cases and internally in 2 cases. With ultrasonography, 8 lesions were hypoechoic, and one was hyperechoic. All three lesions had a high signal intensity on both T1- and T2-weighted images.

CONCLUSIONS

Lipomas had a specific range of computed tomography Hounsfield unit values and also displaced the surrounding soft tissue. Although some variation in the ultrasonographic appearance was observed, the lesions tended to be hypoechoic. These findings may be useful for diagnosing lipomas in the orofacial region.

Breast conserving treatment versus modified radical mastectomy in Japanese patients with operable breast cancer

From January, 1988 to October, 1995, 96 patients with operable breast cancer were treated by breast conserving treatment (BCT) including wide excision and axillary dissection followed by breast radiation. During the same period, 188 patients were treated by modified radical mastectomy (MRM) with or without breast reconstruction. In order to compare the survival of BCT and MRM groups, univariate and multivariate analyses were performed in this retrospective study. Univariate analysis revealed that the 5-year survival rates in the BCT and MRM groups were 97% +/- 2% and 87% +/- 3%, respectively (p < 0.05 with the Cox-Mantel test). However, the baseline variables were different between the groups. The adjusted Cox regression analysis revealed that the results of BCT were almost equivalent with those of MRM. Moreover, no breast recurrence was found in the BCT group. Therefore, it is suggested that our technique of BCT is as effective as modified radical mastectomy in treating operable breast cancer in Japanese patients.

[Alteration of p15 and p16 gene in gastric cancer]

We analyzed p15 and p16 gene alterations in gastric cancer. Only MKN45 showed both homozygous deletions but other cell lines and all of tumor specimens did not show any alterations. Using RT-PCR analysis, decreased or no expression of the p16 gene was found in 1 of 7 cell lines (except MKN45) (14.2%) and in 8 of 20 tumors (40%), whereas no abnormalities of p15 gene expression were found. These results suggest that the p16 gene may correlate with tumorigenesis and tumor expansion due to decrease or loss of gene products in gastric cancer.

[Jejunal pouch interposition and distal gastrectomy]

We developed a new technique of reconstruction in Billroth 1 gastrectomy, jejunal pouch interposition (JPI). The interposed jejunal segment consists of a proximally double-plicated pouch and a distally isoperistaltic conduit. From 1987 to 1994, the JPI was performed on 102 patients with gastric carcinoma. The postoperative functional assay was carried out at least one year later after surgery. Sixty-five patients with the conventional Billroth 1 reconstruction (B-1) during the same period were employed as the control. Gastric emptying time estimated with scinti-scanning was significantly delayed in the JPI group compared with the B-1 group (p < 0.05). All individuals with JPI had meals three times a day whereas 13% of those with B-1 required those more than three times (p < 0.05). The incidence of dumping syndrome was significantly lower in the JPI group (6%) than the B-1 group (20%) (p < 0.05). The reflux of bile into the residual stomach was observed in the scintiscanning at 78% of patients with B-1 whereas 10% of those with JPI (p < 0.01). Endoscopy revealed that regurgitation gastritis was significantly decreased in the JPI group compared with that in the B-1 group (p < 0.01). These results suggest that the JPI prevents small stomach syndrome, dumping syndrome and alkaline reflux gastritis after the B-1 reconstruction.

Evidence of presentation of multiple HIV-1 cytotoxic T lymphocyte epitopes by HLA-B*3501 molecules that are associated with the accelerated progression of AIDS

We recently showed HLA-B35-restricted CTL activity for 10 HIV-1 epitopes in PBL from two HIV-1-infected individuals. In the present study, we established CTL clones specific for nine of these HIV-1 epitopes to confirm these HLA-B35-restricted epitopes. The specific CTL clones effectively killed the HLA-B*3501-positive target cells infected with the HIV-1 vaccinia recombinant virus. These results confirmed that nine HIV-1 CTL epitopes are presented by HLA-B*3501 molecules. The CTL activity specific for four Pol and two Nef epitopes was induced in the peptide-stimulated PBL from three or more of seven HIV-1-infected individuals, indicating that these six are common epitopes. Eight were considered strong epitopes because the specific CTL activity was detected in the cultured PBL that was once stimulated with peptides. Thus, the present study excluded the possibility that the disability of the presentation of HIV-1 epitopes by HLA-B35 molecules is associated with the accelerated progression of AIDS in HLA-B35-positive individuals. Analysis of mutated epitopes found in an HIV-1 type B strain using the CTL clones revealed that most mutated epitopes partially or markedly affect the recognition of CTL clones. Of 19 mutations that affected recognition of the CTL clones, 7 reduced peptide-HLA-B*3501 binding, while 12 affected TCR recognition. These results indicate that natural mutations of HLA-B35-restricted HIV-1 CTL epitopes affect the recognition of CTL by mechanisms that reduce both peptide binding and TCR recognition.

Evidence of presentation of multiple HIV-1 cytotoxic T lymphocyte epitopes by HLA-B*3501 molecules that are associated with the accelerated progression of AIDS

We recently showed HLA-B35-restricted CTL activity for 10 HIV-1 epitopes in PBL from two HIV-1-infected individuals. In the present study, we established CTL clones specific for nine of these HIV-1 epitopes to confirm these HLA-B35-restricted epitopes. The specific CTL clones effectively killed the HLA-B*3501-positive target cells infected with the HIV-1 vaccinia recombinant virus. These results confirmed that nine HIV-1 CTL epitopes are presented by HLA-B*3501 molecules. The CTL activity specific for four Pol and two Nef epitopes was induced in the peptide-stimulated PBL from three or more of seven HIV-1-infected individuals, indicating that these six are common epitopes. Eight were considered strong epitopes because the specific CTL activity was detected in the cultured PBL that was once stimulated with peptides. Thus, the present study excluded the possibility that the disability of the presentation of HIV-1 epitopes by HLA-B35 molecules is associated with the accelerated progression of AIDS in HLA-B35-positive individuals. Analysis of mutated epitopes found in an HIV-1 type B strain using the CTL clones revealed that most mutated epitopes partially or markedly affect the recognition of CTL clones. Of 19 mutations that affected recognition of the CTL clones, 7 reduced peptide-HLA-B*3501 binding, while 12 affected TCR recognition. These results indicate that natural mutations of HLA-B35-restricted HIV-1 CTL epitopes affect the recognition of CTL by mechanisms that reduce both peptide binding and TCR recognition.

Section of the vagal celiac branch in man reduces glucagon-stimulated insulin release

The purpose of this study was to determine whether section of the celiac branch of the vagus nerve in man affects the insulin response to intravenous glucagon injection. Patients who received a subtotal gastrectomy with lymph node dissection for gastric carcinoma were divided into two groups: the celiac-preserved group (n = 16) and the celiac-sectioned group (n = 13). The hepatic branches of the vagus were preserved in both groups. The glucagon test was performed twice in each patient during the operation; before and after manipulation of the celiac branch. Blood samples were collected just before and 6 min after the injection. No difference in the mean increases in blood glucose, insulin and C-peptide levels were seen between the two groups before the nerve manipulation. In the celiac-preserved group, the glucagon stimulated glucose-related C-peptide ratio (x 10(-3) was 0.5 +/- 0.7 before the nerve manipulation and 3.5 +/- 3.0 after it, a significant difference (p < 0.01). In the celiac-sectioned group, this increase was not observed, the ratio was 0.7 +/- 0.6 before the nerve manipulation and 0.8 +/- 3.4 after. These results indicate that the vagal celiac branch in man may also be involved in the control of pancreatic insulin release.

Genomic organization and characterization of the gene encoding bovine prostaglandin F2alpha receptor

We isolated genomic clones for bovine prostaglandin (PG) F2alpha receptor by the standard plaque hybridization method, using the cDNA fragments of bovine PGF2alpha receptor (PGF2alphaR) as probe DNAs. The coding regions of this receptor gene were interspersed by a large intron sequence (33 kb) at the splice junction in the sixth transmembrane domain. The 5'-RACE experiments revealed two alternative transcription start points (tsp), indicating the existence of two potential promoter regions. The major promoter, which was named promoter region A, was located upstream of exon 1 and lacked the typical TATA sequence and CAAT box but had three GC boxes with an overall high GC content. Another putative promoter, region B, was found upstream of exon 2 and had both a TATA-like sequence and a CAAT-like box with several potential binding sites for transcription factors. Southern blot analysis indicated that a single copy gene in the haploid genome encodes PGF2alphaR. Promoter activities of these two putative promoter regions were assayed in the bovine luteal cells, and one of them (promoter region A) was activated by phorbol 12-myristate 13-acetate (TPA) treatment.

Inhibitory actions of endothelial products on mechanical and calcium responses in aortic smooth muscle cells

The effects of endothelial products on intracellular calcium ion concentrations ([Ca2+]i) were investigated in the guinea-pig aorta. The perfusate of bradykinin-stimulated cultured endothelial cells relaxed aortic rings by approximately 70%; it was reduced to approximately 50% by nitroarginine, to approximately 30% in high-K solution and remained unaltered by indomethacin. The perfusate elevated the cyclic GMP content in the muscle, which was inhibited by nitroarginine. In cultured, aortic muscle cells, bradykinin elevated [Ca2+]i with an initial transient and following sustained phase; the former was absent after treatment with cyclopiazonic acid while the latter was abolished in [Ca2+]o-free medium. The perfusate lowered aortic [Ca2+]i, and this action was weakened by nitroarginine and diminished in high-K solution. Therefore, the perfusate reduced aortic [Ca2+]i with and without an increase in cyclic GMP production. These actions were sensitive to nitroarginine and high-K, respectively, suggesting that the perfusate contained at least two relaxants, EDRF and EDHF, with both lowering [Ca2+]i in aortic muscle mainly by inhibiting Ca2+ influx.

Application of fuzzy reasoning in an expert system for ultrasonography

OBJECTIVES

To apply fuzzy reasoning in a computer-assisted diagnostic system for ultrasonography and to evaluate its clinical utility as a diagnostic aid for the unskilled clinician.

METHODS

A computer-assisted diagnostic system for ultrasonography was constructed to differentiate metastatic from inflammatory lymph nodes. The pattern of a skilled clinician's considerations was simulated with the fuzzy expert system. Three fuzzy production rules were set up according to the diagnostic criteria for lymphadenopathy. Each rule was transformed into a membership function. The max-min composition method was used for inference and the centroid method for defuzzification. The system was tested with 20 clinicians who were one to three years after graduation and inexperienced in ultrasonography. Accuracy, sensitivity and specificity were evaluated.

RESULTS

The average increase in accuracy was 8.5%, and the sensitivity and specificity 10.7% and 6.4% respectively. These scores were significant for accuracy (P = 0.005), sensitivity (P = 0.02) and specificity (P = 0.036).

CONCLUSIONS

Application of fuzzy reasoning in an expert system for ultrasonography improves the diagnostic performance of inexperienced clinicians.

Gustatory receptor cell responses to the sweeteners, monellin and thaumatin

Mouse gustatory responses to sucrose, monellin and thaumatin were examined extracellularly from the chorda tympani nerve and intracellularly from individual taste receptor cells. Although monellin and thaumatin taste intensely sweet to humans and old-world monkeys, they do not appear to elicit chorda tympani nerve responses in rats and other mammals. However, there is considerable species variation in the taste responses of mammals, including differences in taste responses of different strains of mice. In the present study with Slc:ICR mice, we show that chorda tympani and taste receptor cell response profiles, and behavioral results for monellin and thaumatin, are similar to response profiles for sucrose.

Binding of 8-mer to 11-mer peptides carrying the anchor residues to slow assembling HLA class I molecules (HLA-B*5101)

The binding of 303 8-mer to 11-mer peptides carrying the anchor residues at P2 and the C-terminus to HLA-B*5101 molecules was examined by a stabilization assay in which peptides were incubated with RMA-S-B*5101 cells at 26 degrees C for 3 h. Analysis of the binding of these peptides to HLA-B*5101 molecules showed that Pro and Ala at P2, and Ile, Val, and Leu at the C-terminus functioned as anchor residues, while Gly at P2 and Met at the C-terminus were weak anchors. Pro was a stronger anchor residue than Ala at P2, while Ile was the strongest anchor at the C-terminus. Among 8-mer to 11-mer peptides, the 9-mer peptides showed the strongest binding to HLA-B*5101 molecules. This is in contrast to our recent findings that 10-mer and 11-mer peptides bind to HLA-B*3501 molecules as effectively as 9-mer peptides. Since both HLA class I molecules have the same B-pocket and the binding peptides carry the same anchor residues, it is assumed that the structure of the F-pocket may restrict the length of binding peptides. The ability of HLA-B*5101 binding peptides to stabilize the HLA-B*5101 molecules was markedly lower than that of HLA-B*3501 binding peptides to stabilize the HLA-B*3501 molecules. It is known that HLA-B*5101 is a slow assembling molecule, while HLA-B*3501 assembles rapidly. The results imply that the slow assembling of HLA-B*5101 molecules results from the low affinity of peptides to HLA-B*5101 molecules.

Tastes activate different second messengers in taste cells

Taste signal transduction occurs in the microvillous membrane of taste cells. Previously, we hypothesized that c-GMP may mediate sweet taste transduction. Some data indicated that IP3 may have a role in vertebrate bitter taste transduction. Here we report that the different second messengers are activated by different tastes. We used techniques designed for radioimmunoassay measurement. The results indicate that sucrose triggers an increase in c-GMP concentration and quinine increases the IP3 concentration in mouse taste cells. These results support the sweet and bitter taste transduction hypotheses.

Suppression of prostaglandin E receptor signaling by the variant form of EP1 subtype

A cDNA clone of prostaglandin (PG) E receptor EP1 subtype (rEP1) was isolated from a rat uterus cDNA library. It encodes 405 amino acid residues with seven transmembrane-spanning domains and couples to Ca2+ mobilization. In addition, three cDNA clones encoding a variant form of rEP1 were isolated. The open reading frame can code a 366-amino acid protein carrying a specific change of 49 amino acids from the middle of transmembrane segment VI to COOH terminus; it possesses a transmembrane segment VII-like structure lacking an intracellular COOH-terminal tail. Southern blot analysis of rat genomic DNA and genomic polymerase chain reaction demonstrated that these cDNAs were derived from a single copy gene. Northern blot analysis and ribonuclease protection assay revealed that both rEP1 and rEP1-variant receptor mRNAs were highly expressed in the kidney. Immunoblot with an antibody directed toward the specific region of rEP1-variant receptor showed that rEP1-variant receptor protein was expressed in the membrane of the kidney and Chinese hamster ovary (CHO) cells transfected with rEP1-variant cDNA. Thus, the rEP1-variant receptor is translated from mRNA which is not spliced at nucleotide position 952 in the segment VI transmembrane region. rEP1-variant receptor retained the ligand binding activity with affinity and specificity similar to rEP1 receptor, but lost the coupling of signal transduction systems by itself. However, when rEP1-variant receptor was stably co-expressed with rEP1 receptor in CHO cells, the Ca2+ mobilization mediated by EP1 receptor was significantly suppressed. Furthermore, when rEP1-variant receptor was expressed in CHO cells, cAMP formation by activation of endogenous EP4 receptor was strongly blocked. These results suggest that the rEP1-variant receptor may affect the efficiency of signal coupling of PGE receptors and attenuate the action of PGE2 on tissues.

Refined peptide HLA-B*3501 binding motif reveals differences in 9-mer to 11-mer peptide binding

HLA-B*3501 is associated with subacute thyroiditis and fast progression of AIDS. An important prerequisite to investigate the T-cell recognition of HLA-B*3501-restricted antigens is the characterization of peptide-HLA-B*3501 interactions. In this study, peptide-HLA-B*3501 interactions were determined in quantitative peptide binding assays. The results were statistically analyzed to evaluate the influence of both anchor and nonanchor positions and the predictability of peptide binding. The binding data demonstrated that all anchor residues at position 2 and the C-terminus found in 9-mers functioned equally as anchors in 10-mers and 11-mers. These minimum requirements of peptide binding were refined by assessing positive and negative effects of nonanchor residues. Aliphatic hydrophobic residues at positions 3, 5, and 8 of 10-mers and position 3 of 11-mers significantly enhanced HLA-B*3501 binding. Similar effects rendered aromatic, bulky residues, acidic or polar residues of 11-mers at position 1 as well as at positions 4, 8, and 10, respectively. Negative effects were observed for residues carrying positively charged side-chains at position 7 of 11-mers. The refined HLA-B*3501 peptide binding motifs enhanced the identification of potential T-cell epitopes. The disparity between positive effects at the middle and C-terminal part (positions 5 - 8 and 10) of 11-mers and shorter peptides supports the extrusion of 11-mer residues at positions 5, 6, and 7, away from the HLA-B*3501 binding cleft.

Apoptosis of mouse naive T cells induced by recombinant soluble Fas ligand and activation-induced resistance to Fas ligand

We have investigated the susceptibility of mouse T cells at various maturation and activation stages to recombinant soluble mouse Fas ligand (termed WX1). CD4+CD8+ thymocytes were preferentially killed by WX1, although CD4+CD8- and CD4-CD8+ thymocytes were also killed at higher concentrations of WX1. The majority of CD4-CD8- thymocytes were resistant to the same doses of WX1. Naive peripheral T cells were also killed by WX1 at concentrations similar to those for single-positive thymocytes. Activation-induced cell death of previously activated T cells is known to be mediated by Fas and Fas ligand. However, the activation of naive splenic T cells by mAbs against CD3/TCR complex rather induced resistance against WX1. This resistance was induced in activated T cells but not in bystander T cells. These mechanisms seem to explain why activated T cells are not immediately killed and why bystander T cells are not activated in an Ag-nonspecific manner.

Apoptosis of mouse naive T cells induced by recombinant soluble Fas ligand and activation-induced resistance to Fas ligand

We have investigated the susceptibility of mouse T cells at various maturation and activation stages to recombinant soluble mouse Fas ligand (termed WX1). CD4+CD8+ thymocytes were preferentially killed by WX1, although CD4+CD8- and CD4-CD8+ thymocytes were also killed at higher concentrations of WX1. The majority of CD4-CD8- thymocytes were resistant to the same doses of WX1. Naive peripheral T cells were also killed by WX1 at concentrations similar to those for single-positive thymocytes. Activation-induced cell death of previously activated T cells is known to be mediated by Fas and Fas ligand. However, the activation of naive splenic T cells by mAbs against CD3/TCR complex rather induced resistance against WX1. This resistance was induced in activated T cells but not in bystander T cells. These mechanisms seem to explain why activated T cells are not immediately killed and why bystander T cells are not activated in an Ag-nonspecific manner.

[Clinical usefulness of serum CYFRA21-1 in colorectal cancer]

Serum CYFRA21-1 levels were studied in 127 cases of colorectal cancer. The positive rates for serum CYFRA21-1 were 34.6% in primary colorectal cancer. There was a significant correlation between the positive rates of serum CYFRA21-1 and liver metastases, peritoneal dissemination, lymph node metastases, or clinical stage. The survival rate for patients in the CYFRA21-1 positive group was lower than those with CYFRA21-1 negative group. Among patients who underwent curative operation, patients is the CYFRA21-1 positive group gave a recurrence rate of 26.6%, against 9.4% in the CYFRA21-1 negative group. There was no correlation between serum CYFRA21-1 levels and serum CEA levels. These findings suggest that Serum CYFRA21-1 levels may be a useful indicator in estimating the prognosis for colorectal cancer.

Reflux of duodenal or gastro-duodenal contents induces esophageal carcinoma in rats

Esophageal adenocarcinoma arises from Barrett's esophagus, which is induced by gastro-esophageal reflux. This refluxate often contains duodenal contents, whose backflow triggers gastric carcinoma, suggesting the hypothesis that refluxed duodenal contents cause esophageal carcinoma. This study examines the role of duodenal and gastric reflux in the absence of exogenous carcinogens in esophageal carcinogenesis. Wistar male rats, 120 in all, each weighing approximately 250 g, were used. Three experimental procedures were performed to produce gastro-duodeno-esophageal reflux, duodeno-esophageal reflux and gastro-esophageal reflux, for comparison with 2 control procedures, Roux-en-Y reconstruction and a sham operation. The animals were fed a standard diet and were examined 50 weeks after surgery. While no carcinoma was found among the 16 gastro-esophageal-reflux, 11 Roux-en-Y and 12 sham-operation animals, 10 of the 12 animals with gastro-duodeno-esophageal reflux (83%) and 10 of the 13 with duodeno-esophageal reflux (77%) developed esophageal carcinoma. The difference between groups was significant (p < 0.001). Two animals with gastro-duodeno-esophageal reflux had esophageal double and triple carcinomas respectively. Of the 23 carcinomas, 16 were adenocarcinoma, 4 adenosquamous carcinoma, and 3 squamous-cell carcinoma. Adenocarcinoma developed from the columnar-lined epithelium near the esophago-jejunostoma, while adenosquamous and squamous-cell carcinoma arose from the squamous esophagitis. These observations demonstrate that refluxed duodenal contents per so are responsible for esophageal carcinogenesis.

Reflux of duodenal or gastro-duodenal contents induces esophageal carcinoma in rats

Esophageal adenocarcinoma arises from Barrett's esophagus, which is induced by gastro-esophageal reflux. This refluxate often contains duodenal contents, whose backflow triggers gastric carcinoma, suggesting the hypothesis that refluxed duodenal contents cause esophageal carcinoma. This study examines the role of duodenal and gastric reflux in the absence of exogenous carcinogens in esophageal carcinogenesis. Wistar male rats, 120 in all, each weighing approximately 250 g, were used. Three experimental procedures were performed to produce gastro-duodeno-esophageal reflux, duodeno-esophageal reflux and gastro-esophageal reflux, for comparison with 2 control procedures, Roux-en-Y reconstruction and a sham operation. The animals were fed a standard diet and were examined 50 weeks after surgery. While no carcinoma was found among the 16 gastro-esophageal-reflux, 11 Roux-en-Y and 12 sham-operation animals, 10 of the 12 animals with gastro-duodeno-esophageal reflux (83%) and 10 of the 13 with duodeno-esophageal reflux (77%) developed esophageal carcinoma. The difference between groups was significant (p < 0.001). Two animals with gastro-duodeno-esophageal reflux had esophageal double and triple carcinomas respectively. Of the 23 carcinomas, 16 were adenocarcinoma, 4 adenosquamous carcinoma, and 3 squamous-cell carcinoma. Adenocarcinoma developed from the columnar-lined epithelium near the esophago-jejunostoma, while adenosquamous and squamous-cell carcinoma arose from the squamous esophagitis. These observations demonstrate that refluxed duodenal contents per so are responsible for esophageal carcinogenesis.

Reflux of duodenal or gastro-duodenal contents induces esophageal carcinoma in rats

Esophageal adenocarcinoma arises from Barrett's esophagus, which is induced by gastro-esophageal reflux. This refluxate often contains duodenal contents, whose backflow triggers gastric carcinoma, suggesting the hypothesis that refluxed duodenal contents cause esophageal carcinoma. This study examines the role of duodenal and gastric reflux in the absence of exogenous carcinogens in esophageal carcinogenesis. Wistar male rats, 120 in all, each weighing approximately 250 g, were used. Three experimental procedures were performed to produce gastro-duodeno-esophageal reflux, duodeno-esophageal reflux and gastro-esophageal reflux, for comparison with 2 control procedures, Roux-en-Y reconstruction and a sham operation. The animals were fed a standard diet and were examined 50 weeks after surgery. While no carcinoma was found among the 16 gastro-esophageal-reflux, 11 Roux-en-Y and 12 sham-operation animals, 10 of the 12 animals with gastro-duodeno-esophageal reflux (83%) and 10 of the 13 with duodeno-esophageal reflux (77%) developed esophageal carcinoma. The difference between groups was significant (p < 0.001). Two animals with gastro-duodeno-esophageal reflux had esophageal double and triple carcinomas respectively. Of the 23 carcinomas, 16 were adenocarcinoma, 4 adenosquamous carcinoma, and 3 squamous-cell carcinoma. Adenocarcinoma developed from the columnar-lined epithelium near the esophago-jejunostoma, while adenosquamous and squamous-cell carcinoma arose from the squamous esophagitis. These observations demonstrate that refluxed duodenal contents per so are responsible for esophageal carcinogenesis.

Identification of multiple HIV-1 cytotoxic T-cell epitopes presented by human leukocyte antigen B35 molecules

OBJECTIVE

To identify HIV-1 cytotoxic T lymphocyte (CTL) epitopes presented by human leukocyte antigen (HLA)-B35 molecules that are associated with the accelerated progression of AIDS using a reverse immunogenetic approach.

METHODS

8-mer to 11-mer sequences carrying two anchor residues at position 2 and the carboxy-terminus were selected from HIV-1SF2 strain. Sixty-four peptides matched to these sequences were synthesized and tested by a peptide binding assay using RMA-S-B*3501 cells. Peripheral blood lymphocytes (PBL) from two HIV-1-infected donors carrying HLA-B35 were stimulated once-weekly with each HLA-B*3501 binding peptide. The CTL activity of the cultured cells for the HLA-B35-positive target cells loaded with the corresponding peptides was examined after the second and fourth stimulation. Furthermore, the CTL activity of the cultured cells possessing HLA-B*3501-restricted HIV-1 peptide-specific CTL activity were examined for the HLA-B*3501-positive target cells infected with the recombinant vaccinia virus containing corresponding HIV-1 gene.

RESULTS

HIV-1 peptide-specific HLA-B*3501-restricted CTL was induced in PBL of HIV-1 infected donors by in vitro stimulation with 11 out of 27 HLA-B*3501-binding HIV-1 peptides. The specific CTL induced with 10 peptides killed the cells infected with recombinant vaccinia virus expressing the corresponding HIV-1 proteins. Out of these HIV-1 peptide epitopes, two epitopes were also presented by HLA-B51 molecules.

CONCLUSION

In addition to the four HLA-B35-restricted HIV-1 CTL epitopes that have been previously reported, nine HLA-B35-restricted HIV-1 CTL epitopes were identified in the present study. These multiple epitopes will be useful in studies for immunopathogenesis of AIDS.