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Biomedical subjects

T Kurata

Publications and source records attributed to T Kurata.

At least 19 recordsLinked to original sources
PubMed1992

Cross-protection against influenza virus infection afforded by trivalent inactivated vaccines inoculated intranasally with cholera toxin B subunit.

Cross-protection against influenza virus infection was examined in mice, immunized intranasally with a nasal site-restricted volume of inactivated vaccines together with cholera toxin B subunit (CTB) as an adjuvant. The mice were challenged with either a small or a large volume of mouse-adapted virus suspension, each of which gave virgin mice either a predominant upper or lower respiratory tract infection. A single dose of a monovalent influenza A H3N2 virus vaccine with CTB provided complete cross-protection against the small-volume challenge with a drift virus within the same subtype, but a slight cross-protection against the large-volume challenge. A second dose of another drift virus vaccine increased the efficacy of cross-protection against the large-volume challenge. Similar cross-protection against H1N1, H3N2, or B type drift virus challenge was provided in the mice having received a primary dose of a mixture of H1N1, H3N2, and B virus vaccines with CTB and a second dose of another trivalent vaccine. The degree of cross-protection against the small- and the large-volume infection paralleled mainly the amount of cross-reacting IgA antibodies to challenge virus hemagglutinin in the nasal wash and that of cross-reacting IgG antibodies in the bronchoalveolar wash, respectively. On the other hand, in mice immunized subcutaneously with the trivalent vaccines having no cross-reacting IgA antibodies, the efficacy of cross-protection was not so high as that of nasal vaccination. These results suggest that the nasal inoculation of trivalent vaccines with CTB provides cross-protection against a broader range of viruses than does the current parenteral vaccination.

Administration, Intranasal↗
PubMed1992

Superior cross-protective effect of nasal vaccination to subcutaneous inoculation with influenza hemagglutinin vaccine.

Intranasal (i.n.) vs. subcutaneous (s.c.) administration of influenza hemagglutinin (HA) vaccine was systematically compared in BALB/c mice. Mice were immunized with different vaccines, together with cholera toxin B subunit as an adjuvant, and 4 weeks later were challenged with either a small (2 microliters) or a large (20 microliters) volume of mouse-adapted A/Guizhou-X (H3N2) virus, each of which gave virgin mice either a nasal or a lung predominant infection. Both i.n. and s.c. inoculations of A/Guizhou-X vaccine conferred almost complete protection against both challenges, i.n. inoculation of A/Fukuoka (H3N2) or A/Sichuan (H3N2) vaccine conferred almost complete cross-protection against 2-microliters challenge and a partial cross-protection against 20-microliters challenge, whereas the s.c. inoculation conferred no cross-protection against 2-microliters challenge with a partial cross-protection against 20-microliters challenge. Moreover, i.n. immunization of PR8 (H1N1) vaccine gave a slight cross-protection against 2-microliters challenge, while the s.c. inoculation did not. The degree of protection was easily improved by i.n. inoculation of higher doses of vaccine, but not by the s.c. inoculation. In parallel with the protection, the i.n. vaccination produced a high level of cross-reacting IgA and IgG antibody to A/Guizhou-X HA in nasal and broncho-alveolar washes, while the s.c. vaccination produced the cross-reacting IgG antibody alone. Thus, i.n. inoculation with inactivated vaccines, which induces cross-reacting anti-HA IgA antibody as well as IgG antibody, is more effective than s.c. vaccination for providing cross-protection against drift viruses.

Administration, Intranasal↗
PubMed1992

Detection of capsid antigen of human papillomavirus (HPV) in benign lesions of female genital tract using anti-HPV monoclonal antibody.

We established a murine monoclonal antibody (K1H8) to human papillomavirus (HPV) using alkaline-disrupted virions of HPV type 1 (HPV-1) as the immunogen. K1H8 recognized a 57 kD capsid protein of HPV-1 and detected the antigen in paraffin sections of formalin-fixed tissue. With K1H8, we examined immunohistochemically 68 biopsy specimens obtained from the female genital tract. The specimens were histologically condyloma acuminatum or koilocytotic lesions with or without dysplasia and each specimen was found to harbour a single type of genital HPV, such as types 6, 11, 16, 18, 31, 33, 42, 51, 52, 56, and 58, by Southern blot hybridization analysis. The antigen was localized in the nuclei and occasionally in the cytoplasm of squamous cells showing koilocytotic changes. Eighty-four per cent of the specimens (57 cases) showed positivity for the antigen, indicating that K1H8 is a broadly-reactive antibody to various genital HPVs. The results suggest that benign mucosal lesions of the female genital tract are more frequently associated with viral production and are a potential source of transmission.

Animals↗
PubMed1992

Identification of epitopes associated with different biological activities on the glycoprotein of vesicular stomatitis virus by use of monoclonal antibodies.

Thirteen monoclonal antibodies (MAbs) to the glycoprotein (G) of vesicular stomatitis virus (VSV) serotype Indiana were prepared and examined for their effects on various biological activities of VSV, including in vitro infection, hemagglutination, adsorption to cells, and mediation of cell fusion. Competitive binding assays with these MAbs revealed the presence of at least seven distinct antigenic determinants (epitopes) on the G protein. In some cases, overlappings among epitopes to various degrees were observed as partial inhibition or binding enhancement. The MAbs to all the epitopes but one (epitopes 1-6) reacted with the denatured G protein in a Western immunoblot analysis. Four of the epitopes (epitopes 2, 4, 5, and 7) were involved in neutralization and two (epitopes 1 and 2) in hemagglutination inhibition. None of the MAbs inhibited the adsorption of radiolabeled VSV to BHK-21 cells; the MAbs to epitope 2 slightly enhanced the virus adsorption. All neutralization epitopes except epitope 2 (epitopes 4, 5, and 7) were associated with inhibition of VSV-mediated cell fusion. These results show a direct spatial relationship between the epitopes recognized by the MAbs and functional sites on G protein and further insights into the structure and function of G protein.

Adsorption↗
PubMed1992

Localization of herpes simplex virus type 1 in sebaceous glands of mice.

The distribution of HSV-1 during the development of zosteriform skin lesions in SCID mice was analyzed by immunofluorescence and electron microscopy. The virus initially appeared within certain keratinocytes, sometimes surrounded by keratinocytes whose surfaces were also positive for the antigens, in the lower epidermal layers including the hair follicles, and then extended upward to the entire epidermis and downward to the sebaceous glands 1-2 days later, when no macroscopic skin lesion was seen. The affected epidermal cells subsequently degenerated and lost their viral antigens within a day, when the zosteriform lesion then became evident. This was followed by a degeneration of the dermis. The sebaceous glands eventually degenerated in 10 days, but some glands in the necrotic skin areas preferentially retained HSV-1. The horizontal spread of the virus in the epidermis beyond the first invaded dermatome occurred much later. In mice passively immunized with specific immune serum, viral antigens were observed even 20 days after the infection in sebaceous glands in necrotized areas. Therefore, HSV-1 appears to spread first via the extracellular fluid among the keratinocytes after being shed from nerve endings, and then produces a successive degeneration of the affected keratinocytes which may prevent any further extension of horizontal viral spread. The pilosebaceous apparatus is possibly acting as a site not only for the replication of HSV-1 with a delayed cytopathic effect, but also as an area that is temporarily sheltered from host defense mechanisms.

Animals↗
PubMed1992

Immunohistochemical study of skin lesions in herpes zoster.

Thirty-seven biopsy skin tissues of herpes zoster taken from 27 patients were analysed immunohistochemically using two monoclonal antibodies detecting either nucleocapsid or glycoproteins of varicella-zoster virus (VZV) on paraffin sections of formalin fixed tissues. Skin lesions of herpes zoster were divided clinically into four stages: erythematous, vesicular, pustular and ulcerative. In the erythematous stage, VZV antigens, if detected, were found only within ballooning cells in the lower epidermis or follicular epithelium. In the vesicular stage, antigens were detected in the cells around and within the intraepidermal vesicles and in histiocytes or fibrocytes of the dermis in all cases and in the endothelial or perineural cells in 10 of 14 cases. In the pustular stage, the antigens were observed in degenerated or necrotic keratinocytes and multinucleated giant cells within pustules and some necrotic cells in the dermis. In the ulcerative stage, the viral antigens were detected only at the ulcer margin and around the hair shaft in 2 of 7 cases. These results suggest that VZV initially involves the epidermis in the erythematous stage, subsequently invades the dermis in the vesicular stage, and disappears in the early ulcerative stage.

Antigens, Viral↗
PubMed1992

Stimulation of the transepithelial flux of influenza HA vaccine by cholera toxin B subunit.

Secretory antibodies in mucosal surfaces are known to play an essential role in protection against various infectious diseases. To enhance the production of such antibodies, influenza HA vaccine was inoculated intranasally into rabbits, together with cholera toxin B subunit (CTB) which is known to augment antibody response to an unrelated antigen. This combination resulted in high levels of serum IgG antibody responses against HA and CTB molecules, 3-4 weeks after inoculation, compared with the inoculation of HA vaccine alone. The adjuvant mechanism for CTB was studied by using Ussing chambers, in which nasal mucosa from rabbits were mounted. CTB was found to enhance the transepithelial flux of HA vaccine, from the mucosal side (lumen) into the serosal side (lamina propria), indicating that the permeability of the membrane was changed by CTB. Moreover, to achieve effective flux of HA vaccines, some interactions between the vaccine and CTB across the membrane were found, which may effect the effectiveness of the vaccine formulation. The results suggest that one of the mechanisms by which CTB enhances the production of mucosal antibody response is to enhance the transepithelial influx of vaccine into the nasal mucosa, where the cells involved in the antibody production are located. CTB may be used as a potent adjuvant to induce antibody response, by nasal vaccination, against pathogens impinging on mucosal surfaces.

Adjuvants, Immunologic↗
PubMed1992

Presence, distribution and spread of productive varicella zoster virus infection in nervous tissues.

Nervous tissue lesions were retrospectively studied for detection of productive varicella zoster virus (VZV) infection in 33 autopsied cases, including 19 herpes zoster (HZ) (10 trigeminal, nine spinal) and 14 cases of nodular brainstem encephalitis without HZ. Immunocytochemistry for VZV antigens and in situ hybridization with a biotinylated VZV DNA probe were used on formol-fixed paraffin sections. Peripheral and central nervous system, skin and striated muscle were investigated in serial sections; available tissue blocks, however, varied between cases. Varicella zoster virus production (both antigen and DNA) in nervous tissue was found in HZ cases but only of short survival after a rash of up to 7 wks (eight out of 12 patients). Varicella zoster virus was visualized in nerve cells, glial cells, Schwann cells and blood vessels. In the central nervous system (CNS), VZV was detected in trigeminal nuclei (one out of 10 brains) or disseminated nodular brainstem lesions (one out of 10 brains), in subependymal microvessels (one out of 10 brains) or vasculitic arteries (two out of 19 brains or spinal cords). In the peripheral nervous system (PNS), VZV (DNA and antigen) was found in neurons and satellite cells of sensory ganglia (four out of seven cases with sampling of ganglia), and in damaged nerve fibres including a muscle nerve in one case; myositis with VZV in affected muscle fibres was found in the latter case. In nodular brainstem encephalitis, one case contained VZV within nodular lesions. We conclude that (i) VZV neural spread is suggested by detectable virus in ganglia, nerve fibres and CNS target nuclei; (ii) haematogenous spread of VZV is suggested by detection of virus in CNS microvessels and in disseminated brainstem encephalitis; (iii) VZV myositis may occur in zosteric myotomes; and (iv) VZV is a possible agent in nodular brainstem encephalitis.

Adult↗
PubMed1992

Experimental infection of cynomolgus and African green monkeys with human herpesvirus 6.

Cynomolgus and African green monkeys were inoculated with human herpesvirus 6 (HHV-6). An antibody response was first observed 10 days and 5 days after inoculation of cynomolgus monkeys and African green monkeys, respectively, and was detectable for the duration of the experiment (33 days). HHV-6 DNA was first detected by the polymerase chain reaction in mononuclear cells of one cynomolgus monkey and one African green monkey 10 days after virus inoculation, and in a total of three of four cynomolgus monkeys (75%) and four of five African green monkeys (80%) later after inoculation. Furthermore, HHV-6 DNA was detected in the lymph nodes and spleen of monkeys killed 33 days after virus inoculation. A rash was observed on the trunk of one African green monkey 13 days after virus inoculation, otherwise the infection was asymptomatic. When mononuclear cells from both groups of monkeys were cultured in medium containing concanavalin A and interleukin 2, and infected with HHV-6 in vitro, virus replication was observed. The data suggest that HHV-6 infects these species of monkey and that this system could be useful as an animal model of HHV-6 infection.

Animals↗
PubMed1992

Detection of herpes simplex and varicella-zoster virus DNA by field-inversion gel electrophoresis from clinical materials.

A simple method using field-inversion gel electrophoresis (FIGE) was applied to detect herpes simplex virus (HSV) and varicella-zoster virus (VZV) genomes in clinical specimens. The whole genomes of these viruses could be detected in small vesicle tissues by the FIGE method regardless of their clinical stages of skin lesions. And the sensitivity of the FIGE method was equivalent to that of an immunofluorescent (IF) method. These data indicated usefulness of the FIGE method to detect the whole genomes of HSV and VZV in clinical specimens.

DNA, Viral↗
PubMed1992

Human herpesvirus 6 (HHV-6) infection in the central nervous system.

Human herpesvirus 6 (HHV 6) was isolated from patients with exanthema subitum (ES) with a high frequency, and it is now believed that this virus causes ES as a primary infection in childhood. HHV 6 infection is highly prevalent in early childhood and this virus may infect infants through the saliva mainly from mother to child. HHV 6 has a tropism to CD4+ cells and destroys cells in vitro. Although children recover from ES without any sequelae, neurological symptoms associated with exanthema subitum are often observed, and we could detect HHV 6 in the cerebrospinal fluid of ES patients. This result suggests that HHV 6 may invade the central nervous system and cause neurological symptoms.

Antibodies, Viral↗
PubMed1992

Two species of human CRK cDNA encode proteins with distinct biological activities.

Two distinct human CRK cDNAs, designated CRK-I and CRK-II, were isolated from human embryonic lung cells by polymerase chain reaction and by screening of a human placenta cDNA library, respectively. CRK-I differed from CRK-II in that it lacked a 170-nucleotide sequence, suggesting that CRK-I and CRK-II were the products of alternative splicing. The amino acid sequences deduced from these two cDNAs differed in the carboxyl termini and contained one SH2 and either one or two SH3 domains. RNAse protection analysis demonstrated both CRK-I and CRK-II mRNAs in various human cells. Three CRK proteins, of 42, 40, and 28 kDa, were identified in human embryonic lung cells by means of antibodies against the SH2 region and the SH3 region of the bacterially expressed CRK-I protein. Transient expression of CRK-I and CRK-II cDNAs in COS7 cells showed that the former encoded the 28-kDa protein and the latter encoded the 40- and 42-kDa proteins. All human cell lines so far examined expressed the 40-kDa protein; however, expression of the 28- and the 42-kDa proteins was variable. In a comparison of the biological activity of the two human CRK proteins, both proteins were stably expressed in rat 3Y1 cells. All cell lines expressing CRK-I protein showed altered morphology, proliferated in soft agar, and grew as massive tumors in nude mice. Although CRK-II-expressing cells showed a slight morphologic change, they did not make colonies in soft agar or grow in nude mice. These results demonstrate that the two species of human CRK cDNA encode proteins which differ in their biological activities.

Amino Acid Sequence↗
PubMed1992

Fatal encephalitis/encephalopathy in primary human herpesvirus-6 infection.

An encephalitic illness with a fatal outcome occurred in a 9 month old girl with virologically confirmed exanthem subitum. Human herpes-virus-6 (HHV-6) DNA was found in the cerebrospinal fluid at the acute stage of the disease by the polymerase chain reaction, but the virus antigen was not detected in her brain tissue. This suggests that HHV-6-induced encephalitis/encephalopathy may be due to a non-infectious process.

Antigens, Viral↗
PubMed1992

Species-related stereoselective disposition of ofloxacin in the rat, dog and monkey.

1. The stereoselective disposition of ofloxacin (OFLX) was studied in rats, dogs and monkeys after oral administration of racemic OFLX. 2. In rats serum concentrations of (R)-(+)-OFLX were much greater than those of (S)-(-)-OFLX, which is the active form of OFLX. In monkeys, by contrast, serum concentrations of (S)-(-)-OFLX predominated over (R)-(+)-OFLX levels. In dogs there were no differences in AUC or Cmax between the enantiomers. Thus, there exists a species-related difference in the stereoselective disposition of OFLX. 3. In rats the stereoselective differences were mainly due to stereoselective glucuronidation; OFLX is hardly metabolized in dogs, monkeys and humans. 4. In monkeys the AUC of (S)-(-)-OFLX was increased by co-administration of the (R)-(+)-form, indicating that the stereoselectivity of OFLX disposition in monkeys may be caused by competition between the enantiomers for renal excretion, especially for renal tubular secretion.

Administration, Oral↗
PubMed1992

Involvement of antigen-presenting cells in the enhancement of the in vitro antibody responses by cholera toxin B subunit.

The enhancing effect of cholera toxin B subunit (CTB) on primary antibody responses to keyhole limpet haemocyanin (KLH) and the cellular basis of the effect were investigated, using in vitro cultures of mouse spleen cells. CTB (1-100 ng/ml) enhanced anti-KLH IgM, IgG and IgA antibody responses in a dose-dependent manner, when added to the cultures with KLH. This immunoenhancement was antigen specific, but not due to either polyclonal activation of the spleen cells or antigenic cross-reactivity between CTB and KLH. CTB did not affect the kinetics of the anti-KLH antibody responses. Early (Days 0-1) addition of CTB to the cultures enhanced the anti-KLH antibody production, whereas late (Days 5-7) addition of CTB did not. Addition of CTB with KLH to splenic adherent cells (SAC) resulted in a dose-dependent enhancement of the anti-KLH antibody responses, when the SAC were reconstituted with unimmunized non-adherent cells. Moreover, CTB enhanced IL-1 secretion from SAC incubated with KLH. These results suggest that CTB enhances the primary anti-KLH antibody responses in vitro by acting on early events in the responses, and that antigen-presenting cells play a major role in the enhancement.

Adjuvants, Immunologic↗
PubMed1991

Transgenic mice susceptible to poliovirus.

Poliovirus-sensitive transgenic mice were produced by introducing the human gene encoding cellular receptors for poliovirus into the mouse genome. Expression of the receptor mRNAs in tissues of the transgenic mice was analyzed by using RNA blot hybridization and the polymerase chain reaction. The human gene is expressed in many tissues of the transgenic mice just as in tissues of humans. The transgenic mice are susceptible to all three poliovirus serotypes, and the mice inoculated with poliovirus show clinical symptoms similar to those observed in humans and monkeys. Rabbit antipoliovirus serum detects the antigens mainly in motor neurons in the anterior horn of the spinal cord and in nerve cells in the medulla oblongata and pons of the paralyzed transgenic mice. Therefore, cell types sensitive to poliovirus in the central nervous system of the transgenic mice appear to be identical to those of humans and monkeys. Furthermore, many more doses of oral poliovirus vaccine strains than of the virulent strains are required to cause paralysis in the transgenic mice. This may reflect the observation that the virulent strain multiplies more efficiently in the central nervous system than the attenuated strain. Thus, the transgenic mice may become an excellent new animal model to study molecular mechanisms of pathogenesis of poliovirus and to assess oral poliovirus vaccines.

Animals↗
PubMed1991

Cross-protection against influenza A virus infection by passively transferred respiratory tract IgA antibodies to different hemagglutinin molecules.

Mice that were intranasally immunized with different influenza A virus hemagglutinins (HA), derived from PR8 (H1N1), A/Yamagata (H1N1) or A/Fukuoka (H3N2) virus, together with cholera toxin B subunit as an adjuvant, were examined for protection against PR8 infection; PR8 HA and A/Yamagata HA immunization conferred complete protection, while A/Fukuoka HA immunization failed to confer protection. In parallel with protection, PR8 HA-, A/Yamagata HA-, and A/Fukuoka HA-immunized mice produced a high, a moderate and a low level of PR8 HA-reactive IgA in the respiratory tract, respectively. These IgA antibodies were not only higher in content in the nasal secretions, but also more cross-reactive than IgG. The purified IgA antibodies from respiratory tract washings of PR8 HA-immunized mice, which contained the HA-specific IgA corresponding to the amount detected in the nasal wash, were able to protect mice from PR8 challenge when transferred to the respiratory tract of naive mice. The transfer of IgA from A/Yamagata HA-immunized mice also afforded cross-protection against PR8 infection, whereas the IgA from A/Fukuoka HA-immunized mice failed to provide protection. The ability of transferred IgA to prevent viral infection was dependent on the amount of HA-reactive IgA remaining in the respiratory tract of the host at the time of infection. These experiments directly demonstrate that IgA antibodies to influenza A virus HA by themselves play a pivotal role in defence not only against homologous virus infection, but also against heterologous drift virus infection at the respiratory mucosa, the portal of entry for the viruses.

Animals↗