Epitope mapping of Japanese encephalitis virus envelope protein using monoclonal antibodies against an Indian strain

A panel of monoclonal antibodies (MAbs) raised against an Indian strain of Japanese encephalitis (JE) virus was used to map topographically the epitopes on the envelope protein. Two separate clusters of epitopes were revealed. On the basis of reactivity in haemagglutination inhibition (HI), neutralization (NT), passive protection and antibody-dependent plaque enhancement (ADPE) assays with the MAbs, five functional domains (A, B, C, D and E) were delineated. The flavivirus cross-reactive domain for HI (A) was distinct. The JE virus-specific domain for HI (B) was in continuum with those domains representing non-HI JE virus-specific MAbs (C) and flavivirus cross-reactive MAbs (D). Domain E, which mapped close to domain D was represented by two MAbs that reacted with both JE virus and uninfected cell nuclei. Four conclusions can be drawn. (i) Two distinct antigenic domains were associated with HI, (ii) HI and NT in vivo and in vitro were dissociated functions, (iii) ADPE activity was solely linked with the A domain and (iv) all MAbs reacting with epitopes in the B domain had HI/NT/protective activity but failed to show ADPE. The B domain might therefore be considered the most suitable for development of synthetic or genetically engineered vaccines.

Replication of Japanese encephalitis virus in monkey, pig and chick leucocyte cultures

Japanese encephalitis (JE) virus replicated in monkey, pig and day-old chick leucocyte cultures. The titres obtained on days 3 to 5 after infection in monkey, pig and chick leucocyte cultures were comparable. Treatment of monkey leucocyte cultures with the mitogens phytohaemagglutinin P, pokeweed mitogen (PWM), formalinized Staphylococcus aureus (Cowan I) or concanavalin A and pig leucocytes with PWM did not significantly affect their ability to support replication of JE virus. No relationship was observed between the amount of [3H]thymidine incorporated in untreated or mitogen treated monkey or pig leucocyte cultures and the titres of JE virus in such cultures. The ability of monkey, pig and chick leucocyte cultures to support JE virus replication was abrogated following silica treatment. These findings suggest that monocytes may serve as one of the important sites of JE virus replication.

Regulation of cell-mediated immunity in mice immunised with Salmonella enteritidis

The effects of diverse factors, such as route of immunisation, composition of immunogen and administration of interferon inducer, on the expression of cell-mediated immune responses against Salmonella enteritidis were investigated in BALB/c and Swiss white mice. Immunisation with live cells of S. enteritidis by the intraperitoneal route (ip) generated both delayed type hypersensitivity (DTH) and protective cell-mediated immunity (CMI). However, the two responses showed diametrically opposite time kinetics. The decline and disappearance by 9 weeks after ip immunisation of DTH and the rise of protective immunity in the same period suggested the possibility that the two responses were mediated by different subsets of T cells. Immunisation by the intradermal (id) route with a sonicate of S. enteritidis generated only DTH; id immunisation also suppressed the development of the protective response following ip immunisation with live S. enteritidis. Both responses were not seen when T cells were eliminated with anti-T cell serum. Oral immunisation with live cells of S. enteritidis induced excellent CMI expressing both DTH and protective responses. On the other hand, oral immunisation with the sonicate of S. enteritidis not only did not induce CMI, but also prevented the development of the DTH and protective response to ip immunisation with live S. enteritidis. Induction of interferon by the administration of poly I: poly C for four consecutive days after id immunisation with killed S. enteritidis suppressed the generation of DTH.

Expression of tumor cell properties in synovial cells in culture

The tumorigenic properties of human rheumatoid arthritis synovial cells in culture were investigated. The synovial cells developed good colonies and secreted plasminogen activator (PA) and collagenase in the cell cultures, as do Hela cells. Since PA and progesterone receptor (PgR) are considered to be end products of estradiol action in breast cancer cells, the estrogen receptor (ER) and PgR content in these cells was also assayed. Large amounts of ER and PgR were detected in the synovial cells in culture, even though these cells are not targets for sex steroids. Study of the cytomorphologic changes in the synovial cells in culture revealed many characteristics generally observed in neoplastic cells. Whether any or all of these observations have any implication in prognosis or therapy in this disease remains to be studied.

Muscular strains in different modes of load handling

The influence of posture on the ability of a person to hold loads was evaluated from a study on six healthy, young males. The muscle activities in terms of isometric strength and electromyographic (EMG) characteristics of the trunk and lower limb were determined in ten load-holding postures. The postures were comprised of trunk, knee and elbow in different straight and bent positions to include load heights (LH) of 32, 44, 85 and 125cm from the ground and subject-load distance (SLD) of 12 and 32cm. The pull-up maximum voluntary contraction (MVC) was significantly influenced by the SLD. The MVC values were consistently high with the increase in LH, when the SLD was 12 cm but the opposite was the case for SLD of 32 cm. The trunk-bent/knee-straight postures had higher MVC values (31 ± 8 to 34 ± 2·5 kgf) than those in knee-bent/trunk-straight postures (21 ± 3 to 28 ± 5 kgf). The trunk muscles behaved differently in trunk-straight and in bent postures. The hamstrings and quadriceps were counter-balanced in sharing loads during knee-bent or straight postures. It was observed that the load-holding operations were performed better in trunk-bent/knee-straight postures, and when the load was closer to the body at heights ranging from 32 to 44 cm. Whereas, in trunk and knee-straight postures, the pulling of the load was more convenient from waist height.

Prediction of biological behaviour of human breast cancer using multiple parameters. A preliminary study

Prediction of early metastases in individual patients has been attempted by combined evaluation of a battery of recognised parameters such as blood vessel invasion (BVI) of tumor cells, Barr body frequency (BBF), plasminogen activator (PA), collagenase, estradiol receptors (ER), progesterone receptors (PgR), and peroxidase activity (PRA) in 18 malignant and 3 benign (control) breast tumors. Since breast tumor cells spread through the blood vessels, the cases were divided into BVI (+) and BVI (-) groups. Results show that in the former group, all the cases had poor prognosis and two even had distant metastases within one year. In BVI (-) group, 9 out of 12 appeared to have good prognosis.

Barr body frequency in esophageal cancer in Indian women

In a retrospective study, Barr body frequency was analyzed in 50 consecutive cases of esophageal cancer in females. The majority (95%) of the tumors had less than 20% Barr body frequency (of which 80% showed less than 10%), while normal controls showed 30% to 45% Barr body frequency. The mechanism(s) involved in lowering the frequency is not known at present.

Interferon induction by flavi- and orbiviruses in L-M cell line

Interferon (IFN) inducing ability of six flaviviruses was compared with five orbiviruses in mouse fibroblast cells (L-M). Orbiviruses were found to induce significantly higher amounts of IFN than flaviviruses.

Behavior of Human Breast Tumor Cells in Vivo on Chorioallantoic Membrane. A Preliminary Report

The invasive properties of 2 types of breast cancers were tested on an « in vivo » model system in which 9-day-old chorioallantoic membrane (CAM) of chick embryo was used. Similar to HeLa and ALL cells, the breast « negative » cells invaded the blood vessels of the host, whereas the breast « positive » cells were seen in the mesoderm away from blood vessels of the host. This finding probably explains the intrinsic aggressive property of breast « negative » cells.

Probable mechanism for the loss of Barr body in human female tumor with special reference to breast cancer

One of the X-chromosomes by a random inactivation process condenses to form X-chromatin (Barr body) in early embryonic life. Once this occurs, it is final and fixed for that cell and all its descendants (1,2). However, numerous investigators have observed extreme variations in Barr body frequency in tumour cells. For example, Sohval and Gains (3) reported an absence of the characteristic Barr body pattern of 19 of the 27 teratomas from females and Moore and Barr (4) observed significant variation in Barr body counts in breast cancer cells. Furthermore, a good correlation was made between the frequency of Barr body and prognosis (5,6,7,8,9). From a retrospective study, it was shown that tumours with low Barr body frequency (BBF) had a significant correlation with blood vessel invasion (BVI) and poor prognosis (10). But the reason why patients with low BBF in the tumor with BVI get early recurrence is not known. In this paper an attempt has been made to suggest a mechanism which may be involved in reducing the BBF with high malignant potentiality.

Interferon (type-alpha and gamma) production by fresh and cryopreserved human mononuclear cells. Brief report

A comparative study of interferon (IFN) production (type-alpha and gamma) was carried out using Ficoll-hypaque purified fresh and cryopreserved mononuclear cells from eight normal healthy individuals. Newcastle disease virus-NDV (R2B strain) was used as an inducer for type-alpha and Staphylococcal enterotoxin-A-(SEA) for type-gamma IFN production. There was no significant difference between the titres of type-alpha and gamma-IFN and lymphocyte subpopulations of fresh and cryopreserved mononuclear cells studied under identical conditions.

Further studies on the prognostic importance of Barr body frequency in human breast cancer: with discussion on its probable mechanism

Based on the Barr body frequency, a total of 285 unselected breast cancer tissues were categorised as negative and positive tumours; incidence of these two groups in our series was 2:1, respectively. When 2-years' disease-free interval and 10-years' survival were considered, it was seen that patients harbouring negative tumours had significantly early recurrence and shorter duration of survival as compared to those having positive tumours. As vascular spread is the prerequisite of early recurrence, the shorter survival in the patients having negative tumours could be explained on the basis of blood vessel invasion, in that 73% of the negative tumours had blood vessel invasion, in contrast to only 24% in the positive tumours.

Loss of X-chromatin and X-chromosome activation in HeLa cells

Activation of second X-chromosome by the action of estradiol-17 beta was studied with HeLa cells. The incidence of X-chromatin in estrogen-treated cells decreased remarkably from 55% to 6%. Further, heavy incorporation of 3H-uridine occurred in the X-chromatin bodies of the treated cells while no such labelling was observed in controls. There was also a manifold increase in the activity of the enzyme G-6-PD in steroid-treated cells, and this increase in enzyme activity could be inhibited by addition of actinomycin D. A nonestrogenic steroid such as testosterone had no effect on these parameters. These observations do indicate activation of second X-chromosome of HeLa cells by estradiol-17 beta.

H-Y antigen in human intersexuality

The status of H-Y antigen was studied in 10 intersexual cases (three pure gonadal dysgenesis with XY genotype, three Klinefelter's syndrome, two true hermaphroditism with XX genotype, two male hermaphroditism) and in 18 normal adult subjects (nine males and nine females). In all these subjects, fluorescent staining and G-banding on chromosomes from cultured leukocytes confirmed their karyotype. Interestingly, H-Y antigen was found to be negative in XY females with dysgenetic gonads (PGD), while in the remaining intersexual states (viz Klinefelter's syndrome, true hermaphroditism and male hermaphroditism), it was found to be positive. These observations confirm that morphological differentiation of testis is controlled by H-Y antigen, and indicate that in the absence of the H-Y antigen, the gonad in pure gonadal dysgenetic patients (46, XY) could not be differentiated into testis, Further, it appears that H-Y antigen in no way influences the secretory function of testis.