Poliomyelitis control in Israel, the West Bank and Gaza Strip: changing strategies with the goal of eradication in an endemic area.

Israel has faced the challenge presented by epidemic poliomyelitis by using different immunization strategies. In the 1950s, inactivated poliovirus vaccine (IPV) helped to reduce the total burden of the disease, but cases continued to occur. Introduction of oral poliovirus vaccine (OPV) in mid-1961 had a dramatic effect in controlling an extensive epidemic of poliomyelitis; however, poliovirus activity and cases continued during the 1970s, and at a low level in the 1980s. A localized outbreak of 15 cases of poliomyelitis in 1988 occurred in an area using enhanced potency IPV (eIPV) only. This led to a revision of poliomyelitis immunization policy. The successful poliomyelitis control in the West Bank and the Gaza Strip using both OPV and IPV since 1978 shows the advantages of a combined approach. This programme was therefore adopted in modified form in the whole of Israel, the West Bank and Gaza. Since late 1988, no cases of poliomyelitis have occurred in any of these three areas, indicating the success of the combined poliomyelitis immunization programme. These experiences may be helpful to other countries, especially those where there is a danger of importation of wild poliovirus, and to prevent vaccine-associated disease. The combined approach provides an additional immunization model in the international effort to eradicate poliomyelitis.

Susceptibility to HIV-1 infection of a human B-lymphoblastoid cell line, DG75, transfected with subgenomic DNA fragments of Epstein-Barr virus.

We have previously shown that the presence of the EBV genome and active EBV infection in some Burkitt's lymphoma cell lines confer the susceptibility of HIV-1 infection in spite of the absence of surface CD4 receptors in these cells. In the present study we used an EBV genome negative Burkitt's lymphoma B-cell line, DG75, transfected with three different subgenomic fragments of EBV expressing the nuclear antigens (EBNA1 and EBNA2) and the latent membrane protein (LMP), respectively. Immunofluorescence analysis demonstrated CD4 expression in more than 90% of the EBNA1, EBNA2 and LMP transfected cell lines, whereas the antigen could only be detected in less than 4% of the parental DG75 cell line. Unlike the wild type DG75 line, the three transfected cell lines were shown to be susceptible to HIV-1 by both IFA and production of virions. Northern blotting of poly(A) selected mRNA of the four cell lines and hybridization to a human CD4 cDNA (pT4B) demonstrated a 3 kb band in all three EBNA1, EBNA2 and LMP transfected cells as well as in the wild type DG75 cells. Approximate quantification indicates equivalent level of T4 mRNA expression in the transfected cell lines as compared to T-cell lines (Hut-78, H9-9).

Use of a combined DTP-polio vaccine in a reduced schedule.

A five-year serologic follow-up and a four-year monitoring of the polio and pertussis morbidity in an area immunized with a 2 + 1 dose schedule of a combined DTP-Po vaccine have shown that: the individual protection against polio measured by the presence of neutralizing antibody persists at a very adequate level five years after the first booster; after three years of a steady high proportion of children with pertussis antibody, a considerable drop is observed and in about 28% of individuals agglutinin levels of less than 1:20 were found five years after booster; the community protection against paralytic poliomyelitis and pertussis is satisfactory up to four years after the introduction of the program. Continuation of immunization with a 2 + 1 dose schedule at a maximal coverage and close seroepidemiologic surveillance are necessary in order to draw definite conclusions, because of the potentially strong impact of very dynamic ecological factors present in our geopolitical area upon the agent-host interrelationship.

Inhibition of mating by naloxone or morphine in recently castrated, but not intact male rats.

Administration of naloxone (SC 5 mg/kg) significantly reduced ejaculation and mounting in male rats in the weeks following castration. A similar effect was obtained by injecting morphine (SC 1 or 5 mg/kg). In contrast, the same dosages of naloxone or morphine did not affect the sexual performance of gonadally intact males. Opioid peptides may contribute to the temporary persistence of sexual behavior in testosterone-deficient male mammals, in which incentive qualities of the female partner are an important determinant of sexual arousal.

A modified schedule for routine pertussis immunization.

As part of a study with a quadruple inactivated vaccine (diphtheria-pertussis-tetanus-polio), the serologic response to the pertussis antigen was investigated in infants at the age of routine immunization, inoculated with one of the following two regimens: either 0.5 ml vaccine at 2 and 3 1/2 months and a booster six months later, or an identical dose of vaccine given at 2, 4 and 6 months and a booster at the age of 12 months. A pertussis agglutination titer of greater than or equal to 1:10 was considered an immune response to the administration of the antigen. Two basic doses of pertussis antigen induced an immune response in about 92% of children, which was very close to that following three basic doses. A 100% seroconversion was observed in both groups one month after the booster dose, and geometric mean values were high in both regimens. At one and two years after the booster, the pertussis agglutinins were present in 100% of children of both groups, with higher geometric mean values in the group given the three basic doses regimen.

Prevalence of antibodies to respiratory syncytial virus in various populations in Israel.

A preliminary study on the prevalence of antibodies to respiratory syncytial virus (RSV) in individuals of various age-groups was carried out. In healthy infants aged 6 to 12 months, the prevalence was 27%. It increased to 37 and 54% in children aged 1 to 2 and 2 to 4 years, respectively. The prevalence reached 78% in healthy individuals who were more than 20 years old, including pregnant women. Significant levels of specific antibodies were detected in 59% of children aged 6 to 12 months who were hospitalized with respiratory tract illnesses. It appears that acquisition of antibodies to RSV in our population occurs relatively later in life than in other Western countries.

The Israeli experience in the control of poliomyelitis during a quarter of a century, 1957-1982.

Data are presented on the programs and the results of immunization against paralytic poliomyelitis in Israel during the 25-year period 1957-1982. To control severe outbreaks of the disease, Israel introduced Salk-type inactivated poliovirus vaccine (IPV) on a large scale in 1957 and used it for a period of five years. Vaccination with IPV had a beneficial effect, demonstrably reducing the morbidity from poliomyelitis. In 1961, Sabin's oral poliovirus vaccine ( OPV ) was first used during an epidemic outbreak of the disease and has been in continuous use since. Vaccination with OPV has resulted in a highly significant decrease in the incidence of the disease, although sporadic cases continued to occur. This program was supplemented for the past four years with an annual mass vaccination campaign in "high-risk" areas of the country. These additional preventive measures have resulted in a further reduction in morbidity but not in the complete disappearance of the disease.

Comparison of inactivated poliovirus vaccine and oral poliovirus vaccine programs in Israel.

In spite of high vaccination coverage, paralytic poliomyelitis still occurs in Israel, either in sporadic form in the urban area or in small outbreaks in the rural, non-Jewish segment. At high risk are mainly very young infants, not yet protected by poliovirus vaccine and children who have failed to seroconvert after a full course of oral poliovirus vaccine ( OPV ). In these circumstances, a new program for vaccination of young infants early in life with a quadruple vaccine containing inactivated poliovirus vaccine (IPV) and diphtheria, tetanus, and pertussis vaccines (DTP) has been tested. Administration of two doses of IPV up to the age of three and one-half months followed by a booster at the age of 10 months has produced a very satisfactory antibody response (100% seroconversion and high geometric mean titers of antibody to the three antigens), which has occurred early in life and persisted up to two years after booster. This response was similar to that observed after four doses of trivalent OPV ( TOPV ) reinforced with one dose of monovalent type 1 OPV . Two doses of the quadruple vaccine have also induced an antibody response to pertussis antigen in greater than 90% of the infants. After booster, a greater than 99% conversion rate has been recorded, which has remained unchanged at one year of follow-up. The above data have led to the modification of the poliovirus vaccination schedule in the areas at risk.

Results of a program successfully combining live and killed polio vaccines.

Oral polio vaccine (OPV) has been used in the Gaza Strip since 1968. Although vaccine coverage had reached 80 to 90% of the infant population, the epidemiological pattern of the paralytic disease had not changed significantly as of the beginning of this study. The mean annual incidence continued to be around 10/100,000. Two outbreaks occurred, in 1974 and 1976, involving 75 and 77 children, respectively, an incidence of 18/100,000. In these two outbreaks, 34 and 50% of the affected children, respectively, received 3 to 4 doses of OPV. A serological survey done after a vaccination campaign with monovalent Type 1 vaccine showed an unexpectedly low percentage of seropositives. A parallel was found between the prevalence of diarrheal disease and vaccine failure, and a causal effect was postulated. To overcome this problem, a program of immunization was started early in 1978 combining both live and killed polio vaccines. Although cases of polio continue to appear, the incidence has been reduced to 2.4/100,000 population. In 1981, only one case was reported, in an unvaccinated child. Thus, it would seem that the new vaccination schedule combining live and killed vaccines makes eradication of polio a possibility.

Hybridization between a human epithelial line, infectable by Epstein-Barr virus, and Burkitt lymphoma lines: membrane properties, superinfectability, inducibility and tumorigenicity.

The human epithelial line U, which is partially infectable with EBV, was hybridized with the EBV-genome carrying Burkitt lymphoma lines P3HR-1 and Daudi. Authenticity of the hybrids U-Put and U-Dut was established by isoenzyme studies. Although the two hybrids carried the EBV genome derived from the lymphoma parent, being 100% positive for Epstein-Barr-virus-associated nuclear antigen (EBNA), they resembled the U parent in many respects: they were deficient for membrane immunoglobulins and Fc receptors, and had a lower concentration of EBV-C3 receptors than either parent. Unlike the P3HR-1 parent, U-Put hybrid was nonpermissive for both the EBV cycle antigens, early antigen (EA) and viral capsid antigen (VCA). The inducing agent 12-O-tetra-decanoyl-phorbol-13-acetate (TPA) caused distinct viral early antigen synthesis (EA) in U-Put, lower, however, than that of the parental P3HR-1. U-Dut was completely nonpermissive and noninducible for early and viral capsid antigens. Thus, even an epithelial parent infectable by EBV restricted, although not completely, expression of EBV antigens, with the exception of EBNA. It has been suggested that EBNA is an autonomous function of the viral genome, independent of host cell control; the latter regulates expression of antigens related to viral cycle. The hybrids U-Put and U-Dut resembled the U parent also in regard to growth in soft agar and tumorigenicity in nude mice, although in this respect the lymphoma parental properties were not completely eclipsed.

Induction of Epstein-Barr virus nuclear antigen and DNA synthesis in a human epithelial cell line after Epstein-Barr virus infection.

The association of Epstein-Barr virus (EBV) with nasopharyngeal carcinoma is supported by the presence of EBV genomes in the epithelial elements of the tumor and by elevated antibody titers to EBV-specific antigens in the patients; the levels of these titers are related to the clinical course of the disease. However, since most laboratory data suggest that EBV is a B-lymphotropic virus, it is unclear how the virus becomes associated with the epithelial elements of the nasopharynx. The purpose of the present work was to find a human model system to study this association. A human epithelial line (U) was found that could be directly infected by EBV, and viral functions, the induction of EBV nuclear antigen and cellular DNA synthesis, were demonstrated. The U line was established in 1957 by the late H. J. Van Kooten (Kok-Doorschodt at the University of Utrecht), and although it is no longer diploid, it exhibits density inhibition. When U cells were infected with EBV, EBV nuclear antigen was expressed in 6 to 16% of the cells, 1 and 2 days after infection with B95-8 virus, but not with the P3HR-1 strain. No evidence for virus replication was obtained; immunofluorescence staining for early antigens and virus capsid antigens gave negative results. Quantitative adsorption experiments for EBV indicated that the adsorption capacity of U cells is significant (60% of Raji cells). The present results also demonstrated that infection with the virus overcomes block(s) in cellular DNA synthesis caused by 5-fluorodeoxyuridine. The induction of DNA synthesis was determined by increased incorporation of [3H]thymidine into the cells. The highest level of isotope incorporation was observed at about 15 h after infection and thereafter decreased. Analysis of the induced DNA indicated that it was of cellular origin.

Organophosphorous compounds as inhibitors of EBV infection and transformation.

Phosphonoformic acid trisodium salt (PF), ethyl diethyl-phosphonoformate (Et-PF), phosphonoacetic acid (PAA), ethyl diethyl phosphonoacetate (Et PAA), ethyl diethyl-2-phosphonopropionate (Et-2-PPA) and ethyl diethyl-3-phosphonopropionate (Et-3-PPA) were tested as inhibitors of EBV virus capsid antigen (VCA) synthesis in B.95-8 cells by immunofluorescence. The most effective inhibitors were: PF, inhibition of 96.74 percent of VCA synthesis at a concentration of 500 microM and PAA, inhibition of 82.05 percent of VCA synthesis at a concentration of 250 microM. Much higher concentrations of the other compounds were needed for inhibition with lower efficiency. Synthesis of EBV nuclear antigen (EBNA) was not inhibited by PF or PAA. However, only PF and PAA inhibited the transformation of human cord blood lymphocytes (CBL) by EBV, as measured by 3H-thymidine uptake, even when added 24 hours after infection. The degree of inhibition of transformation correlated with the concentration. Complete inhibition of CBL transformation by EBV was achieved by 1,000 microM PF and 500 microM PAA, which were noncytotoxic. Removal of PAA from B.95-8 cells cultivated in the presence of high concentrations of PAA for 15 weeks restored VCA synthesis without full concomitant production of transforming EBV.

Antibodies to human T lymphocytes in xenoantisera elicited with a new immature T-cell line (Peer).

Peer, a continuous line of immature T lymphocytes, was recently established from a patient with T-cell leukemia. In the present study antisera elicited in rabbits by immunization with Peer cells and absorbed with B cells were found to react with a distinct T-lymphocyte antigen. Absorbed anti-Peer serum was highly cytotoxic for human thymus cells and exerted a preferential activity on peripheral T lymphocytes. Peripheral blood lymphocytes (PBL) surviving exposure to anti-Peer serum and complement were depleted of most of the cells forming E rosettes, whereas the proportion forming EAC' rosettes was increased. Similarly, the depletion of cells forming E rosettes resulted in a concomitant reduction of the sensitivity of PBL to the cytotoxic effect of anti-Peer serum, while the enrichment of E-rosette forming cells had the opposite effect. Anti-Peer serum did not inhibit the formation of E rosettes by PBL in the absence of complement. Absorbed anti-Peer serum failed to exert any cytotoxic effect not only on normal B lymphocytes but also on the CBL and IMB B-cell lines, yet maintained a cytotoxic activity on the Raji and Daudi cell lines. A possible interpretation of these results is that immunization with Peer cells, a line of immature T lymphocytes, leads to the production of antibodies to a distinct antigen expressed on thymus and peripheral T cells. The antigen seems to be absent from normal peripheral B lymphocytes, but may be expressed on a line of pre-B cells, such as the Raji and Daudi lines.

A controlled trial with inactivated poliovaccine.

A trail with inactivated polio vaccine (IPV) was carried out, aiming at the earliest possible vaccination of young infants from rural settlements, before their exposure to type 1 wild poliovirus, highly prevalent in the environment. One hundred and fifteen infants were primed at the age of 2 and 3 1/2 months with the quadruple antigen DPT-polio. When 10 months old, 61 were boosted with the same antigen, and 54 with TOPV associated with DTP. Another 53 babies fed with TOPV at 2, 4, 6 and 12 months were used as a control. One dose of IPV produced antibody to polio type 1 in 83% of babies. With two doses of IPV a 100% response was obtained. Six months after the second dose, a small decrease in the percentage of infants wih detectable antibody to type 1 was observed, but at one month after the booster a highly significant anamnestic response was achieved. The results with IPV compared favorably with the immune response of infants given TOPV. Details on the results of the field trial will be presented, and field implementations of IPV will be discussed.