Nonimmune Monkeys Research Articles

Comparative study of anti-measles immunity in adult population of Sochi and laboratory primates of Adler primate center

Aim. Comparative study of the level of anti-measles immunity in monkeys of the Primate Center , colony service staff and in some groups of the population of the Adler region. Materials and methods. In this study 1077 sera have been investigated : 354-from humans and 723-from monkeys. Commercial test systems were used to determine IgG and IgM antibodies to measles virus by IEA (immune enzyme analysis). Results. An extremely low degree of anti-measles immunity among monkeys of different species of the Adler Primate Center (10,2±1,4%) at the expense of the individuals born before 1993 was revealed. In cynomolgus monkeys (Macaca fascicularis) imported from Vietnam and the Republic of Mauritius in 2015-2017 the rate of detection of anti-IgG varied from 2.3% to 57.5%. Anti-IgM was no detected. The rate of anti — measles immunity in the adult population was generally below normal (86.4±1.8%), but varied in different groups (57.8-100%). A significant difference was found (p≤0.05) not only in the percentage of individuals with the immunity to measles virus among persons aged 18-35 compared with persons aged 36-75 years (73.6±3.5% and 96.9±1.2%, respectively), but also in the average antibody titers (1.34±0.26 IU/ml and 2.92±0.24 IU/ml, respectively). The lowest percentage of seropositive individuals (57.8±6.2%) and antibody levels (0.97±0.21 IU/ml) were observed in a group of students (18-25 years old). Conclusion. The presence of individuals (26.4%) seronegative to the measles virus among young people aged 18-35 years supports the necessity of vaccination against measles. The emergence of a source of infection among nonimmune monkeys (89.8%) born after 1992 may lead to an outbreak of measles.

Construction, safety, and immunogenicity in nonhuman primates of a chimeric yellow fever-dengue virus tetravalent vaccine.

We previously reported construction of a chimeric yellow fever-dengue type 2 virus (YF/DEN2) and determined its safety and protective efficacy in rhesus monkeys (F. Guirakhoo et al., J. Virol. 74:5477-5485, 2000). In this paper, we describe construction of three additional YF/DEN chimeras using premembrane (prM) and envelope (E) genes of wild-type (WT) clinical isolates: DEN1 (strain PUO359, isolated in 1980 in Thailand), DEN3 (strain PaH881/88, isolated in 1988 in Thailand), and DEN4 (strain 1228, isolated in 1978 in Indonesia). These chimeric viruses (YF/DEN1, YF/DEN3, and YF/DEN4) replicated to ~7.5 log(10) PFU/ml in Vero cells, were not neurovirulent in 3- to 4-week-old ICR mice inoculated by the intracerebral route, and were immunogenic in monkeys. All rhesus monkeys inoculated subcutaneously with one dose of these chimeric viruses (as monovalent or tetravalent formulation) developed viremia with magnitudes similar to that of the YF 17D vaccine strain (YF-VAX) but significantly lower than those of their parent WT viruses. Eight of nine monkeys inoculated with monovalent YF/DEN1 -3, or -4 vaccine and six of six monkeys inoculated with tetravalent YF/DEN1-4 vaccine seroconverted after a single dose. When monkeys were boosted with a tetravalent YF/DEN1-4 dose 6 months later, four of nine monkeys in the monovalent YF/DEN groups developed low levels of viremia, whereas no viremia was detected in any animals previously inoculated with either YF/DEN1-4 vaccine or WT DEN virus. An anamnestic response was observed in all monkeys after the second dose. No statistically significant difference in levels of neutralizing antibodies was observed between YF virus-immune and nonimmune monkeys which received the tetravalent YF/DEN1-4 vaccine or between tetravalent YF/DEN1-4-immune and nonimmune monkeys which received the YF-VAX. However, preimmune monkeys developed either no detectable viremia or a level of viremia lower than that in nonimmune controls. This is the first recombinant tetravalent dengue vaccine successfully evaluated in nonhuman primates.

Lack of viraemia and limited antibody response of dengue virus immune rhesus monkeys after vaccination with DEN-2/S-1 vaccine

A dengue-2 live virus vaccine was tested in monkeys immune to heterologous dengue serotypes to determine if, as with wild DEN-2 virus, antibody-enhanced viraemia and seroconversion would occur. A low dose of 900 plaque-forming units (PFU) of the DEN-2/S-1 vaccine virus was inoculated subcutaneously into rhesus monkeys six months after they had received wild DEN-1, DEN-2 or DEN-3 viruses, and into non-immune monkeys. As previously reported for non-immune monkeys, there was little, if any, detectable vaccine viraemia in any of the groups of monkeys. There was no difference in seroconversion between the dengue heterologously immune ( 3 6 ) and non-immune ( 1 3 ) monkeys. These data indicated that (i) the vaccine virus may differ from the parent virus in the ability to complex with heterologous antibody and, thus, in the ability to infect Fc receptor bearing cells in monkeys; (ii) 10 3 PFU of vaccine virus is approximately the 50% infectious dose in monkeys as measured by seroconversion.

The significance of plasma kinins in malaria

Investigation has been carried out on the various processes which together produce the clinical and pathological picture of malaria.Maegraith [1] suggested the presence of certain ‘initiating factors’ which are thought to be physiologically active substances of relatively simple nature derived from the parasite either as a consequence of host-parasite reaction or arising from tissue damage. A good deal of progress has been made in the search for these initiating factors in malaria and some of our findings indicate clearly that pharmacologically active substances, including kinins, circulate in increased concentration in the blood as the disease progresses. This report, however, illustrates the possible pharmacological role exhibited by plasma kinins in the acute stages of malarial infection. This work was prompted by the experimental evidence reported by other workers of the involvement of blood: brain barrier inPlasmodium knowlesi-infected monkeys andP. berghei-infected mice (Migasena andMaegraith [2]). In both animal species increased passage of albumin through the endothelium of the blood vessels into the brain substance and cerebrospinal fluid was demonstrated at the terminal stages of the disease. This study was carried out on non-immune rhesus monkeys (Macaca mulatta) infected withP. knowlesi. As far as human malaria is concernedP. knowlesi is an important parasite since the disease processes which it induces in rhesus monkeys follow a somewhat similar pattern to that ofP. falciparum in man.

Phytohemagglutinin enhancement of dengue-2 virus replication in nonimmune rhesus monkey peripheral blood leukocytes

Phytohemagglutinin treatment of peripheral blood leukocytes from dengue nonimmune monkeys enhanced dengue-2 virus replication. Enhancement was due primarily to an increase in the number of infected cells. Destruction of mononuclear phagocytes with silica did not significantly inhibit virus replication in phytohemagglutinin-treated cultures. Pokeweed mitogen, concanavalin A, and streptolysin O stimulated increased deoxyribonucleic acid synthesis in monkey leukocytes but did not enhance virus replication. None of the mitogens significantly affected virus replication in cultures of dengue-immune monkey peripheral blood leukocytes.

Dengue viruses and mononuclear phagocytes. I. Infection enhancement by non-neutralizing antibody

Cultured mononuclear peripheral blood leukocytes (PBL) from nonimmune human beings and monkeys are nonpermissive to dengue 2 virus (D2V) infection at multiplicities of infection of 0.001-0.1, but become permissive when non-neutralizing dengue antibody is added to medium. D2V infection occurred in PBL prepared from anti-coagulated but not from defibrinated plasma. Infection enhancement was produced by multiple lots of heterotypic anti-dengue raised in several mammalian species. Homotypic anti-dengue neutralized D2V at high concentrations but enhanced at low concentrations; enhancement end point in one serum was 1:320,000. The infection-enhancing factor was a noncytophilic antibody of the IgG class. D2V infection occurred in the absence of heat-labile complement components but did not occur when complexes were prepared with anti- dengue F(ab)(2). Treatment of PBL with several proteases increased permissiveness to D2V infection by immune complexes but not by virus alone. Two rhesus monkey serums collected 14 days after D2V infection contained an IgG antibody with high-titered enhancing activity but with no hemagglutination-inhibition or neutralizing activity. Virus-antibody complexes are irreversibly attached to PBL within 15 min and completely internalized in 60 min. There was considerable variation in cellular infection in different experiments, however, maximum virus yields usually exceeded 1,000 plaque-forming units per 1 x 10(6) PBL occurring between 2 and 4 days in culture. In vitro antibody-dependent infection of PBL provides a possible model for study of pathogenetic mechanisms in infants with dengue shock syndrome who passively acquire maternal anti-dengue IgG.

Replication of Dengue Viruses in Cultures of Peripheral Blood Leukocytes from Dengue-Immune Rhesus Monkeys

Dengue virus of types 1, 2, and 4 replicated reproducibly in cultures of peripheral blood leukocytes from 18 dengue-immune rhesus monkeys but failed to multiple in peripheral blood leukocytes from 25 nonimmune monkeys. Replication was observed at input multiplicity of infection of 0.1 and 0.01 but irregularly at less than or equal to 0.001. Dengue viruses in permissive leukocytes achieved maximal titers on days 2-4 of culture. Viral replication in peripheral blood leukocytes from animals immune to a different type of dengue virus and in animals immune to two or more types of dengue virus was quantitatively similar to that in peripheral blood leukocytes from homotypically immune donors. Dengue virus permissiveness developed between two and three weeks after primary dengue infections. Leukocytes of animals that developed immunity to dengue virus remained permissive to in vitro infection by dengue virus of types 1 and 2 for prolonged periods, but within six months permissiveness to type 4 decreased. Thus an immunological dependence of in vitro dengue virus replication in simian peripheral blood leukocytes was demonstrated.

Antibody Response in Rhesus Monkeys and Guinea Pigs to Inoculation with RNA Derived from Antigenically Stimulated Cell-Free Systems

Abstract Cell-free systems derived from rhesus monkey or guinea pig spleens were incubated with influenza virus hemagglutinins. The RNA extracted was designated as informational RNA and was found to be capable of inducing specific antibody responses in recipient non-immune rhesus monkeys and guinea pigs. The immunogenic activity of informational RNA was species-specific and sensitive to the action of RNase. Therefore, it was concluded that the antibody responses observed were due to RNA itself and not to traces of antigen possible present. The doses of RNA injected per animal ranged from 0.73 µg to 0.0005 µg. No correlation was found between immunogenic activity and the dose of RNA.

THE PASSIVE TRANSFER OF HUMAN MALARIAL IMMUNITY.

Sotiriades, in 1917, reported clinical improvement in the condition of a patient with acute malaria following the inoculation of 10 ml of serum obtained from a “chronic” case. Kauders confirmed this finding by observing that beneficial effects resulted in 9 of 12 patients who received small quantities of serum from a person difficult to infect with malaria. While these reports suggested that the passive transfer of malarial immunity was feasible the first convincing evidence was adduced by Coggeshall and Kumm. These authors showed that protection against Plasmodium knowlesi could be conferred upon non-immune rhesus monkeys through serum obtained from monkeys previously immunized against this parasite. Although the degree of protection achieved was variable, best results being obtained when parasitic inocula were small, this study clearly indicated the existence of protective antibodies in the blood of monkeys with established malarial infections.

How the Present Poliomyelitis Vaccine Was Discovered

T HE first preliminary tests of the Salk poliomyelitis vaccine were reported in 1953. The making of such a vaccine had become possible, and reasonable grounds for a critical trial of it in man established, through a series of earlier discoveries. In 1908, Landsteiner and Popper first transmitted polio to monkeys by inoculating them with human spinal cord tissue from a fatal case. The next year, Flexner and Lewis confirmed this, and were able to pass the infection from monkey to monkey, using spinal cord tissue from one to inoculate the next. In this way, over the ensuing years, numerous of poliovirus, each from a different human source, were isolated at various laboratories. In 1909 it was further noted that monkeys surviving one attack of polio did not suffer a second when reinoculated with virus of the same strain. Moreover, when blood serum of surviving, immune monkeys was mixed with the strain of virus used originally to infect them, and then used to inoculate normal monkeys, it proved harmless. A similar mixture, of virus and serum of nonimmune monkeys, was by contrast fully infectious. That was the first demonstration of a neutralizing antibody against polio, a substance that appears in the blood of man as well as the monkey, and remains for years as a sign that infection has occurred. Until 1951, there was no way of identifying the virus, in suspected material, except to inoculate monkeys with it and produce the characteristic disease. To be sure that polio would be produced, the inoculation was usually made directly into the animal's brain; polio could be produced only irregularly when the virus was introduced by other routes. It was difficult at first to test for virus except in tissues removed aseptically after death. Body secretions and excretions of living subjects are contaminated with bacteria, which if inoculated into the brain could cause infection more rapidly than polio. Therefore, little was known about the behavior of the virus in living persons or animals until 1937 when methods for killing bacteria without inactivating virus in media containing both, were found. Stock strains of virus were preserved simply as infected monkey spinal cord tissue. When used to inoculate animals it was ground finely and suspended in fluid. The same material was used for experimental vaccines. Vaccination of monkeys was tried in 1910, and for 30 years thereafter, with little success. Some of the vaccines were treated with chemical or other agents designed to inactivate the virus. Vaccines of live, virulent virus also were tried. Most strains of poliovirus can be injected subcutaneously or intramuscularly in monkeys with only an occasional infection resulting. Such vaccines were not of course proposed for use in man, but unless live virus could be shown to immunize, little obviously could be expeced from inactivated-virus vaccines. Monkeys vaccinated with live virus were found to develop antibody rather regularly. When vaccinated monkeys were tested for resistance to infection, by inoculation with live virus in the brain, the results were less encouraging. Paralytic polio often ensued in splite of the presence of antibody in the animal's serum. The results with

Poliomyelitis viruses in tissue culture. III. Susceptibility of testicular tissue from immune monkeys.

SummaryThe titration endpoints of Brunhilde (type 1), Y-SK (type 2), and Leon (type 3) poliomyelitis viruses were uniformly reproducible in roller tube cultures of testicular tissue from 31 of the 34 monkeys tested. The tissue of approximately 10% of the monkeys tested was “incompletely” susceptible to the poliomyelitis viruses. This insusceptible state could not be attributed to the presence of serum antibody. Testicular tissue obtained from immune monkeys supported growth of all 3 antigenic types of poliomyelitis virus comparable to that obtained in tissue of nonimmune monkeys.