[Screening test for hematopoietic stem cells in umbilical cord blood with the SE-9000 automated hematology analyzer]

The immature information IMI channel on an SE-9000 automated hematology analyzer was used for detection of stem cells in cord blood and the results were compared with other standard methods, including flow cytometry analysis and progenitor assays. After the removal of red blood cells, the IMI count in cord blood samples significantly correlated with the number of CD34+ cells (r = 0.810), CFU-GM (r = 0.606) and BFU-E (r = 0.961). The cell count in hematopoietic progenitor cell (HPC) area also showed a correlation with CD34+ cell number (r = 0.722), but to a lesser extent than the IMI count; no significant correlations were observed with the numbers of progenitor cells. Cord blood contained higher fractions of CD34+/CD38- and CD34+/CD117+ cells representative of immature subclasses of progenitor cells. This might explain the difference in the HPC module results for the cord blood and peripheral blood stem cell samples. A higher coefficient of correlation was obtained with leukocyte suspensions than with whole blood samples. These results demonstrated the usefulness of IMI-positive cell measurement as a stem cell screening test for cord blood banking.

Borna disease virus infection in two family clusters of patients with chronic fatigue syndrome

A high rate of Borna disease virus (BDV) infection has been demonstrated in patients with chronic fatigue syndrome (CFS). Herein, we focused on BDV infection in two family clusters of patients with CFS: a father, mother, two sons and one daughter (family #1); and a father, mother, two daughters and one son (family #2). All members, except for the elder son in family #1 and the father and son in family #2, were diagnosed with CFS. The results supported that all the family members with CFS were infected with BDV, as evidenced by the presence of antibodies to viral p40, p24 and/or gp18 and BDV p24 RNA in peripheral blood mononuclear cells. The healthy members, except for the father of family #2 who was positive for antibody to p24, were all negative by both assays. Follow-up studies in family #1 continued to reveal BDV antibodies and BDV RNA, except in the mother, who lost the RNA upon slight recovery from the disease.

A case of successful conservative chemotherapy for intramural pregnancy

OBJECTIVE

To describe a rare case of intramural pregnancy diagnosed with the use of magnetic resonance imaging (MRI) and conservatively managed.

DESIGN

Case report.

SETTING

Department of obstetrics and gynecology in a university hospital.

PATIENT

A 33-year-old healthy patient with a history of a partial mole after 3 years of primary unexplained infertility.

INTERVENTION(S)

Laparoscopic and transvaginal local injections of methotrexate.

MAIN OUTCOME MEASURE(S)

Transvaginal ultrasound (US) and MRI findings.

RESULT

Treatment was successful, with no complications, and the patient's reproductive potential was preserved.

CONCLUSION(S)

Early detection of intramural pregnancy with the use of transvaginal US is important, and MRI is a useful, noninvasive imaging modality. Chemotherapy with methotrexate is an effective treatment that allows preservation of reproductive potential.

Proline-rich antimicrobial peptide, PR-39 gene transduction altered invasive activity and actin structure in human hepatocellular carcinoma cells

PR-39 is an endogenous proline-rich antimicrobial peptide which induces the synthesis of syndecan-1, a transmembrane heparan sulphate proteoglycan involved in cell-to-matrix interactions and wound healing. Previously, we revealed that the expression of syndecan-1 was reduced in human hepatocellular carcinomas with high metastatic potential and speculated that syndecan-1 played an important role in inhibition of invasion and metastasis. It is assumed that a modification of this process with PR-39 and syndecan-1 may result in a new strategy by which it can inhibit the invasion and metastasis. Therefore, we transduced a gene of PR-39 into human hepatocellular carcinoma cell line HLF, which shows a low expression of syndecan-1 and a high in vitro invasive activity, and examined whether this procedure could reduce the invasive activity of tumour cells. In two transfectants with PR-39 gene, the syndecan-1 expression was induced and the invasive activity in type I collagen-coated chamber was inhibited. Moreover, these transfectants showed the suppression of motile activity assayed by phagokinetic tracks in addition to the disorganization of actin filaments observed by a confocal imaging system. In contrast, five transfectants with syndecan-1 gene in the HLF cells revealed suppression of invasive activity but did not alter the motile activity and actin structures of the cell. These results suggest that PR-39 has functions involved in the suppression of motile activity and alteration of actin structure on human hepatocellular carcinoma cells in addition to the suppression of invasive activity which might result from the induction of syndecan-1 expression.

STAT5 as a molecular regulator of proliferation, differentiation and apoptosis in hematopoietic cells

Signal transducers and activators of transcription (STATs) play key roles in growth factor-mediated intracellular signal transduction. In the present study using a constitutively active STAT5 mutant, we show that STAT5 has pleiotropic functions regulating cell proliferation, differentiation and apoptosis in an IL-3-dependent Ba/F3 cell line. The mutant STAT5 possessed constitutive tyrosine phosphorylation and DNA binding activity, induced expression of bcl-xL and pim-1 in the absence of IL-3 in Ba/F3 cells, and rendered Ba/F3 cells factor-independent. Unexpectedly, IL-3 treatment of the factor-independent Ba/F3 cells expressing the constitutively active STAT5 resulted in apoptosis within 24 h, or differentiation followed by cell death. In these cells, mRNA expression of growth inhibitory genes downstream of STAT5 such as CIS, JAB/SOCS-1/SSI-1, and p21(WAF1/Cip1) was highly induced, correlating with prolonged hyper-phosphorylation of the mutant STAT5 after IL-3 stimulation. Of the STAT5-regulated genes, we found that constitutive expression of JAB/SOCS-1/SSI-1 was sufficient to induce apoptosis of Ba/F3 cells, while p21(WAF1/Cip1) could induce differentiation of these cells. In contrast, constitutive expression of pim-1 was sufficient to induce IL-3-independent growth of Ba/F3 cells. These findings suggest that a single transcription factor regulates cell fate by varying the intensity and duration of the expression of a set of target genes.

Induction of germline transcription in the TCRgamma locus by Stat5: implications for accessibility control by the IL-7 receptor

IL-7 receptor (IL-7R) plays critical roles in lymphocyte development by promoting survival and proliferation and by inducing V(D)J recombination in TCR and Ig loci. Here, we demonstrate that IL-7R-activated Stat5 binds to consensus motifs in the 5' regions of Jgamma segments and induces germline transcripts. We also show that a constitutively active form of Stat5 restores V-J recombination of TCRgamma genes and partially rescues T cell development from IL-7R(-/-) T cell precursors, especially in favor of gammadelta T cells. Therefore, this study reveals a potential role of Stat5 in T cell development and also implies that IL-7R may control the accessibility of the TCRgamma locus through Stat5-induced germline transcription.

Effects of photoperiod on salmon GnRH mRNA levels in brain of castrated underyearling precocious male masu salmon

Previous studies have suggested that activation of salmon gonadotropin-releasing hormone (sGnRH)-producing neurons is induced by the combined effects of photoperiod and steroid hormones in underyearling males of the masu salmon, Oncorhynchus masou. The present study further assesses the effects of photoperiod and steroid hormones on sGnRH synthetic activity and examines the changes in sGnRH mRNA levels in the brains of castrated underyearling precocious male masu salmon by manipulating the photoperiod for 60 days from August through October. In castrated males in which plasma testosterone levels decreased to low levels, sGnRH mRNA levels in the preoptic area (POA) increased under a short photoperiod (8L-16D), whereas they remained at low levels under a long photoperiod (16L-8D) for a 2-month duration. In sham-operated males, sGnRH mRNA levels in the ventral telencephalon and those in the POA increased in October with testicular maturation even under a long photoperiod with a delay of 1 month compared with the short photoperiod group. These results suggest that preoptic sGnRH-producing neurons receive short photoperiodic signals and that either short photoperiod or steroid hormone secretion is required for the activation of sGnRH synthesis in underyearling precocious male masu salmon.

Requirement of IL-5 for induction of autoimmune hemolytic anemia in anti-red blood cell autoantibody transgenic mice

IL-5, IL-10 and lipopolysaccharide (LPS) are known to activate B-1 cells in vivo in normal mice and anti-red blood cell autoantibody transgenic mice (HL mice). To assess the exact role of IL-5 in proliferation and activation of peritoneal B-1 cells, we analyzed IL-5 receptor alpha chain-deficient HL (IL-5Ralpha-/- x HL) mice generated by the cross between IL-5Ralpha-/- and HL mice. In IL-5Ralpha-/- x HL mice, Ig-producing B-1 cells in the peritoneal cavity were negligible, although the total number of B-1 cells in the peritoneal cavity were as many as 30% of that in HL mice. Moreover, LPS- or IL-10-induced differentiation of B-1 cells into antibody-producing cells was severely impaired in IL-5Ralpha-/- x HL mice. We also used in vivo 5-bromo-2'-deoxyuridine labeling to estimate the proliferation of B-1 cells in IL-5Ralpha-/- mice. The absence of IL-5Ralpha did not affect spontaneous proliferation of peritoneal B-1 cells. However, induced proliferation of peritoreal B-1 cells by oral administration of LPS was markedly impaired in IL-5Ralpha-/- mice. These results suggest that IL-5 is required for activation-associated proliferation of B-1 cells but not for their spontaneous proliferation and support the idea that IL-5 plays an important role on the induction of autoantibody production from B-1 cells.

Reverse transcriptase (RT)-independent as well as RT-dependent HIV-1 replication exists in syncytia following cell fusion

We studied the role of reverse transcriptase (RT) in human immunodeficiency virus (HIV)-1 replication in syncytia following cell fusion. A chronically HIV-1-infected MOLT-4 (MOLT-4/IIIB) cells allow HIV-1 replication and induce syncytium formation between uninfected MOLT-4 cells. AZT (3'-azido-3'-deoxythymidine, 1 microM) inhibited neither HIV-1 replication in MOLT-4/IIIB cells nor the syncytium formation induced by concultivation of MOLT-4/IIIB cells with uninfected MOLT-4 cells. In the supernatant of the syncytium containing culture a remarkably higher titer of p24 antigen was produced than in that of MOLT/IIIB cell culture. AZT inhibited p24 antigen production by HIV-1 in the syncytia to levels to comparable to that in MOLT-4/IIIB cells which were treated with AZT. In addition, p24 production by HIV-1 in the syncytia formed by cocultivation of CL-2 cells, which are chronically infected with HIV-1 but lack functional RT, with uninfected MOLT-4 cells was not different from that in CL-2 cells alone. The results suggest that HIV-1 RT plays an important role in HIV-1 replication within the syncytia but an RT-independent replication process which is essential for syncytium formation also exists in the syncytia. These results indicate that not only RT inhibitors but also inhibitors of syncytium formation are essential for anti-HIV therapy.

Mercury and other trace metals (Ag, Cr, Co, and Ni) in soft tissue and byssus of Mytilus edulis from the east coast of Kyushu Island, Japan

Concentrations of Hg and other metals such as Ag, Cr, Co and Ni in soft tissues and byssi of the blue mussel (Mytilus edulis) from three sites along the east coast of Kyushu Island, Japan, were determined by a cold-vapor technique. Large inter-regional differences in metal concentrations in both soft tissues and byssi were observed. The tissue concentrations of Hg were significantly greater in M. edulis from the most contaminated locations (Saganoseki) compared to those from a non-industrialized area (Urashiro). It is evident that, compared to the soft tissue, byssus is a more sensitive biomonitor for Hg, Cr, Co and Ni. From the data obtained in the present study evidently results that the soft tissue and especially byssi of M. edulis appear to be good bioindicators for identification of coastal areas exposed to Hg contaminants.

The cellular kinase binding motifs (PxxP and RR) in human immunodeficiency virus type 1 Nef protein are dispensable for producer-cell-dependent enhancement of viral entry

We have recently demonstrated that human immunodeficiency virus type 1 (HIV-1) Nef is required for enhancing viral infectivity by increasing the efficiency of viral entry in a producer-cell-dependent manner, suggesting the possible involvement of a cellular factor(s) in the enhancement of viral entry. Moreover, it has been reported that a proline-rich (PxxP) motif and an Arg-Arg (RR) motif in HIV-1 Nef bind to the SH3 domain of the Src-family tyrosine kinase Hck and to a serine/threonine kinase, respectively. To address whether these cellular kinase binding motifs, PxxP and RR, could be involved in virus producer-cell-dependent enhancement of viral entry, we constructed two nef mutant proviral clones in which these motifs were mutated. The results show that the HIV-1 Nef PxxP motif, which significantly influenced viral infectivity, and the RR motif, which modestly affected viral infectivity, were both dispensable for enhanced viral entry, thus suggesting that another interaction of Nef with a cellular factor(s) is involved in the efficiency of viral entry.

Alymphoplasia is caused by a point mutation in the mouse gene encoding Nf-kappa b-inducing kinase

The alymphoplasia (aly) mutation of mouse is autosomal recessive and characterized by the systemic absence of lymph nodes (LN) and Peyer's patches (PP) and disorganized splenic and thymic structures with immunodeficiency. Although recent reports have shown that the interaction between lymphotoxin (LT) and the LT beta-receptor (Ltbeta r, encoded by Ltbr) provides a critical signal for LN genesis in mice, the aly locus on chromosome 11 is distinct from those for LT and its receptor. We found that the aly allele carries a point mutation causing an amino acid substitution in the carboxy-terminal interaction domain of Nf-kappa b-inducing kinase (Nik, encoded by the gene Nik). Transgenic complementation with wild-type Nik restored the normal structures of LN, PP, spleen and thymus, and the normal immune response in aly/aly mice. In addition, the aly mutation in a kinase domain-truncated Nik abolished its dominant-negative effect on Nf-kappa b activation induced by an excess of Ltbeta r. Our observations agree with previous reports that Ltbeta r-deficient mice showed defects in LN genesis and that Nik is a common mediator of Nf-kappa b activation by the tumour necrosis factor (TNF) receptor family. Nik is able to interact with members of the TRAF family (Traf1, 2, 3, 5 and 6), suggesting it acts downstream of TRAF-associating receptor signalling pathways, including Tnfr, Cd40, Cd30 and Ltbeta r. The phenotypes of aly/aly mice are more severe than those of Ltbr-/- mice, however, indicating involvement of Nik in signal transduction mediated by other receptors.

IL-7 receptor alpha+ CD3(-) cells in the embryonic intestine induces the organizing center of Peyer's patches

Peyer's patch (PP) organogenesis proceeds through three histologically distinct steps: formation of organizing centers expressing VCAM-1 and ICAM-1 in segregated regions of the intestine at 15.5 days post-coitus (d.p.c.) (step I), accumulation of blood cells expressing different sets of surface markers to this region at 16.5-17.0 d.p.c. (step II), and entry of CD3+ and B220+ lymphocytes just before birth (step III). PP formation of both Il7ra-/- and Lta-/- mice is impaired from step I, suggesting involvement of the two molecules at the same timing in PP organogenesis. Expression of lymphotoxin (LT) alpha and LTbeta in IL-7 receptor (IL-7R) alpha+ cells in the intestine indicates that defects of Il7ra-/- and Lta-/- mice are due to functional inability of IL-7Ralpha+ cells in the induction of PP anlage. Blocking of IL-7Ralpha function by a single injection of the antagonistic mAb in 15.5 d.p.c. embryos suppressed appearance of VCAM-1(+) spots and expression of LTalpha and LTbeta in the intestine, which eventually resulted in mice without PP but are otherwise normal. Intestinal IL-7Ralpha+ cells are lymphoid in morphology but CD3(-) and functional in both nu/nu and Rag2-/- mice. These results implicate IL-7Ralpha+ CD3(-) cells as the direct inducer of the organizing center of PP.

Increase of serum des-gamma-carboxy prothrombin in alcoholic liver disease without hepatocellular carcinoma

The purpose of this study is to determine serum des-gamma-carboxy prothrombin (DCP) levels in benign liver diseases by a new sensitive method, and to demonstrate the elevation of serum DCP in alcoholic liver disease (ALD) without hepatocellular carcinoma (HCC). Median values of serum DCP were 16.2 mAU/ml (range: 3.2 to 1570 mAU/ml) in ALD and 16.7 mAU/ml (1.2 to 75.4 mAU/ml) in viral liver disease (VLD). Using the cut-off value of 40 mAU/ml as a tumor marker for HCC, 21% (11/52) was positive in ALD and 2% (1/57) was positive in VLD (p = 0.0014, Fisher's exact probability test), and 27% (9/33) was positive in alcoholic liver cirrhosis and 3% (1/39) was positive in viral liver cirrhosis (p = 0.0042, Fisher's exact probability test). The positive rate of DCP was significantly (p < 0.001, Spearman's rank correlation test) correlated with the severity of liver disease in ALD. Serum vitamin K level was not decreased in cases with ALD. In a demonstrable case, serum DCP was decreased after abstinence and was increased again after the beginning of ethanol intake, suggesting the involvement of ethanol to the elevation of serum DCP in ALD. In conclusion, serum DCP was significantly elevated in ALD, compared with VLD, although the mechanism of the elevation of DCP was not clarified. Ethanol intake may act, in part, on the increase of serum DCP in ALD.

Establishment of persistent infection with HIV-1 abrogates the caspase-3-dependent apoptotic signaling pathway in U937 cells

Treatment of 26L cells, a subclone obtained from U937 cells, with TNF-alpha or DNA-damaging agents such as teniposide (VM26) and camptothecin (CPT) induced morphologically and biochemically typical apoptotic changes, including the activation of procaspase-3. The cells persistently infected with HIV-1 (26L/HIV), however, showed a marked resistance to VM26 and CPT, whereas they hardly lost the sensitivity to TNF-alpha. TNF-alpha-induced apoptosis of 26L/HIV cells proceeded without the increase in caspase-3 activity, indicating that signaling for apoptosis in the infected cells proceeded through an alternative caspase-3-independent pathway which could respond to TNF-alpha but not to VM26 and CPT. The evidence that p-toluenesulfonyl-l-lysine chloromethyl ketone (a trypsin-like serine protease inhibitor) blocked VM26- and CPT-induced apoptotic changes but not TNF-alpha-induced apoptosis also supported the existence of the alternative TNF-alpha-inducible pathway. The results also suggest that a TLCK-sensitive protease is involved upstream of the procaspase-3 activation process and that the protease is essential for the progress of VM26- and CPT-induced apoptosis. The similar effect of HIV-1-productive infection on the apoptosis induced by the DNA-damaging agents was also confirmed by utilizing U1 cells, which are latently HIV-1-infected U937 cells. The cells became resistant to these agents after induction of the viral production by pretreatment with PMA. These results suggest that persistent HIV-1 infection blocks an apoptotic pathway triggered by DNA damaging agents through the inhibition of the procaspase-3 activation process.

Antigen-driven clonal accumulation of peritoneal gammadelta T cells in vivo

How the clonality of gammadelta T cells changes in response to exogenous antigens is uncertain. Here we analyzed kinetics of Vgamma1.1 and Vgamma2 T cell clonality after intraperitoneal injection of purified protein derivatives (PPD) by the heterogeneity of the third complementarity determining region (CDR3) length in Vgamma1.1-Jgamma4-Cgamma4 and Vgamma2-Jgamma1-Cgamma1 junctions. The V-J junctions were analyzed in intrahepatic lymphocytes (IHL), spleen cells, and peritoneal exudate cells (PEC) by polyacrylamide gel electrophoresis. Gammadelta T cells expressing Vgamma1.1 and Vgamma2 genes were heterogeneous in normal mice. Accumulation of specific Vgamma1.1 T cell clones was transiently detected 7 days after the injection in PEC, but no accumulation was observed in IHL and spleen cells. The accumulated clones disappeared by 4 weeks. Transient accumulation of Vgamma2 T cell clones was also observed in PEC at the early phase after the injection. These results suggest that gammadelta T cells with specific TCR respond to PPD and temporary accumulate in the peritoneal cavity, but not in liver and spleen.

High susceptibility of Mongolian gerbil (Meriones unguiculatus) to Borna disease virus

Borna disease virus (BDV) is a neurotropic enveloped virus with a nonsegmented, single-, negative-stranded RNA genome. This virus induced encephalitis in experimentally infected adult rats, but in newborn rats BDV established a persistent, tolerant infection with no apparent clinical signs. Here, we report evidence that newborn Mongolian gerbils (Meriones unguiculatus) are more susceptible to experimental intracranial inoculation of horse-derived BDV in persistently infected MDCK cells, compared with similar inoculation in newborn rats. All inoculated newborn gerbils, but not rats, died 30 days after infection. Reverse transcriptase-polymerase chain reaction amplified BDV-specific sequences in several regions including the brain. Histopathological analysis revealed apparent inflammatory reactions in the brains of inoculated gerbils but not rats, although similar levels of BDV RNA were detected in both gerbil and rat brains. BDV-specific antigen and RNA were identified predominantly in neurons in the brains by immunohistochemistry with antibodies to BDV and in situ hybridization with BDV-specific riboprobes, respectively. BDV in the gerbil brain was easily rescued by co-cultivation of the brain homogenate with human oligodendroglioma cells. Thus, gerbils seem to be a useful animal model for studying BDV-induced pathogenesis in the brain.

The YXXL sequences of a transmembrane protein of bovine leukemia virus are required for viral entry and incorporation of viral envelope protein into virions

The cytoplasmic domain of an envelope transmembrane glycoprotein (gp30) of bovine leukemia virus (BLV) has two overlapping copies of the (YXXL)2 motif. The N-terminal motif has been implicated in in vitro signal transduction pathways from the external to the intracellular compartment and is also involved in infection and maintenance of high viral loads in sheep that have been experimentally infected with BLV. To determine the role of YXXL sequences in the replication of BLV in vitro, we changed the tyrosine or leucine residues of the N-terminal motif in an infectious molecular clone of BLV, pBLV-IF, to alanine to produce mutated proviruses designated Y487A, L490A, Y498A, L501A, and Y487/498A. Transient transfection of African green monkey kidney COS-1 cells with proviral DNAs that encoded wild-type and mutant sequences revealed that all of the mutated proviral DNAs synthesized mature envelope proteins and released virus particles into the growth medium. However, serial passages of fetal lamb kidney (FLK) cells, which are sensitive to infection with BLV, after transient transfection revealed that mutation of a second tyrosine residue in the N-terminal motif completely prevented the propagation of the virus. Similarly, Y498A and Y487/498A mutant BLV that was produced by the stably transfected COS-1 cells exhibited significantly reduced levels of cell-free virion-mediated transmission. Analysis of the protein compositions of mutant viruses demonstrated that lower levels of envelope protein were incorporated by two of the mutant virions than by wild-type and other mutant virions. Furthermore, a mutation of a second tyrosine residue decreased the specific binding of BLV particles to FLK cells and the capacity for viral penetration. Our data indicate that the YXXL sequences play critical roles in both viral entry and the incorporation of viral envelope protein into the virion during the life cycle of BLV.

Fine structure and morphogenesis of Borna disease virus

Borna disease virus (BDV), a negative nonsegmented single-stranded RNA virus, has not been fully characterized morphologically. Here we present what is to our knowledge the first data on the fine ultrastructure and morphogenesis of BDV. The supernatant of MDCK cells persistently infected with BDV treated with n-butyrate contained many virus-like particles and more BDV-specific RNA than that of untreated samples. The particles were spherical, enveloped, and approximately 130 nm in diameter; had spikes 7 nm in length; and reacted with BDV p40 antibody. A thin nucleocapsid, 4 nm in width, was present peripherally in contrast to the thick nucleocapsid of hemagglutinating virus of Japan. The BDV particles reproduced by budding on the cell surface.

Two proline-rich nuclear localization signals in the amino- and carboxyl-terminal regions of the Borna disease virus phosphoprotein

Borna disease virus (BDV) uses a unique strategy of replication and transcription which takes place in the nucleus, unlike other known, nonsegmented, negative-stranded RNA viruses of animal origin. In this process, viral constituents necessary for replication must be transported to the nucleus from the cytoplasm. We report here the evidence that BDV P protein, which may play an important role in viral replication and transcription, is transported into the nucleus in the absence of other viral constituents. This transportation is accomplished by its own nuclear localization signals (NLSs), which are present in both N-terminal (29PRPRKIPR36) and C-terminal (181PPRIYPQLPSAPT193) regions of the protein. These two NLSs can function independently and both have several Pro residues as key amino acids.

Development of peptide vaccines inducing production of neutralizing antibodies against HIV-1 viruses in HLA-DQ6 mice

Peptide vaccines against HIV-1 were prepared according to the cassette theory that we had proposed previously. An amino acid sequence of B subtype consensus of the HIV-1 V3 region was introduced into the MHC binding component with a supermotif for various MHC class II. The peptide vaccines induced T-cell responses in the DQ6 mice in which only DQ6 molecules were expressed as MHC class II. By contrast, an original V3 peptide including the consensus sequence was non-immunogenic in the DQ6 mice. Antibodies obtained from the DQ6 mice immunized with the peptide vaccines neutralized laboratory B subtype strains of HIV-1 in vitro. It may be anticipated that these peptide vaccines protect infection of HIV-1 in DQ6 positive individuals.