A. P. Agafonov

Inactivation of Viruses in Bubbling Processes Utilized for Personal Bioaerosol Monitoring

ABSTRACT A new personal bioaerosol sampler has recently been developed and evaluated for sampling of viable airborne bacteria and fungi under controlled laboratory conditions and in the field. The operational principle of the device is based on the passage of air through porous medium immersed in liquid. This process leads to the formation of bubbles within the filter as the carrier gas passes through and thus provides effective mechanisms for aerosol removal. As demonstrated in previous studies, the culturability of sampled bacterium and fungi remained high for the entire 8-h sampling period. The present study is the first step of the evaluation of the new sampler for monitoring of viable airborne viruses. It focuses on the investigation of the inactivation rate of viruses in the bubbling process during 4 h of continuous operation. Four microbes were used in this study, influenza, measles, mumps, and vaccinia viruses. It was found that the use of distilled water as the collection fluid was associated with a relatively high decay rate. A significant improvement was achieved by utilizing virus maintenance fluid prepared by using Hanks solution with appropriate additives. The survival rates of the influenza, measles, and mumps viruses were increased by 1.4 log, 0.83 log, and 0.82 log, respectively, after the first hour of operation compared to bubbling through the sterile water. The same trend was observed throughout the entire 4-h experiment. There was no significant difference observed only for the robust vaccinia virus.

Experimental study on the possibility of treatment of some hemorrhagic fevers

After intracerebral challenge with 100 PFU of Lassa virus (strain Josiah), all infected mice (CBA/calac) died (control group). Production of pro-inflammatory cytokines (IL-1beta, TNF-alpha) significantly increased in the blood of these mice during the infection. For neutralization of increasing concentrations of these cytokines recombinant IL-1RA was used intraperitonealy at a dose 100 microg kg(-1), everyday, within 5 days from the third day after the challenge. Injections of IL-1RA decreased the concentration of IL-1beta and TNF-alpha and resulted in survival of all infected mice (treatment group). Marburg fever (strain Popp) caused in guinea pigs by 5 LD(50) of virus lead to the significant increase of TNF-alpha in the animals blood and caused a lethal outcome (control group). Treatment of infected guinea pigs by IL-1RA or anti-TNF serum decreased the concentration of TNF-alpha and resulted in survival of half of the animals (treatment group). For the treatment recombinant IL-1RA was used at a dose 100 microg kg(-1), intramuscularly, everyday, within 6 days from the third day after the challenge or anti-TNF serum, intramuscularly 0.5 ml (2000 U ml(-1); 1 U of the antiserum neutralises 0.03 ng of TNF-alpha), everyday, within 6 days from the third day after the challenge.

Monitoring of viable airborne SARS virus in ambient air

Abstract Due to recent SARS related issues (Science 300 (5624) 1394; Nature 423 (2003) 240; Science 300 (5627) 1966), the development of reliable airborne virus monitoring procedures has become galvanized by an exceptional sense of urgency and is presently in a high demand (In: Cox, C.S., Wathers, C.M. (Eds.), Bioaerosols Handbook, Lewis Publishers, Boca Raton, FL, 1995, pp. 247–267). Based on engineering control method (Aerosol Science and Technology 31 (1999) 249; 35 (2001) 852), which was previously applied to the removal of particles from gas carriers, a new personal bioaerosol sampler has been developed. Contaminated air is bubbled through porous medium submerged into liquid and subsequently split into multitude of very small bubbles. The particulates are scavenged by these bubbles, and, thus, effectively removed. The current study explores its feasibility for monitoring of viable airborne SARS virus. It was found that the natural decay of such virus in the collection fluid was around 0.75 and 1.76lg during 2 and 4h of continuous operation, respectively. Theoretical microbial recovery rates of higher than 55 and 19% were calculated for 1 and 2h of operation, respectively. Thus, the new sampling method of direct non-violent collection of viable airborne SARS virus into the appropriate liquid environment was found suitable for monitoring of such stress sensitive virus.

Infection of chickens caused by avian influenza virus A/H5N1 delivered by aerosol and other routes.

This study presents results of the study of infectivity of avian influenza virus (AIV) A subtype H5N1 strains isolated from agricultural birds across the territory of the Russian Federation and CIS countries. The results of the susceptibility of chickens to the AIV isolates delivered by the aerosol route and the dissemination of the virus in the organs of infected birds are presented. As was observed, the sensitivity of birds to AIV by the aerosol route of infection is 30 times higher than by intranasal route, 500 times higher than by the oral route and 10000 times higher than by the intragastric route of infection, which is indicative of higher permissivity of respiratory organs to AIV. The highest titres of AIV A subtype H5N1(A/Chicken/Kurgan/05/2005 strain) in aerosol-infected chickens were found in nasal cavity mucosa, lungs, cloaca, serum and kidney, where viable virus accumulation was detected by 18h post-infection (p.i.). The highest virus titres were observed 54h p.i. in lungs, serum and kidney, reaching the value of 8.16 lg EID50 /g(ml) in the lungs. The results showed that birds infected by the aerosol route developed higher titres of virus than those infected by other routes.

Construction of artificial virus-like particles exposing HIV epitopes, and the study of their immunogenic properties

One of the major problems in the development of successful recombinant vaccines against human immunodeficiency virus (HIV) is that of correct identification of a safe and effective vaccine delivery system with which to induce protective immunity using soluble protein antigens. An original method for constructing artificial immunogens in the form of spherical particles with yeast dsRNA in the center and hybrid proteins exposing epitopes of an infectious agent on the surface is reported. The dsRNA and the proteins were linked with spermidine-polyglucin-glutathione conjugates. Particles exposing HIV-1 epitopes were constructed, and their immunogenicity tested.

Enteric administration of a live attenuated measles vaccine does not induce protective immunity in a macaque model.

To test the option of oral vaccination with a live attenuated measles vaccine (LAV), we have evaluated the potential of an orally administered enteric-coated tablet containing a candidate LAV (strain Leningrad-16, MV-L16). To this end three groups of two cynomolgus macaques each were vaccinated via different routes with 10(3.8) TCID(50) MV-L16 vaccine: intramuscularly (i.m.), intraintestinally (i.i.) upon laparotomy and via enteric-coated tablets. Upon vaccination, MV-L16 could only be isolated from one of the i.m.-vaccinated monkeys and not from any of the other five. Both the i.m.-infected monkeys and one of the i.i.-infected monkeys developed a MV-specific serum antibody response. Also, MV-specific CD8(+) IFN gamma-producing T cells could be demonstrated in all three monkeys that had seroconverted. Upon challenge with wild-type MV 1 year after vaccination, only these three monkeys proved to be protected. These data do not support the viability of the concept of oral vaccination with LAVs.

Оценка чувствительности животных к особо опасным ортопоксвирусам с использованием первичных культур клеток легких

Objective of the study is to investigate the sensitivity of different animals to highly pathogenic Orthopoxviruses applying techniques, based on utilization of primary cultures of lung cells, and to assess the possibility of further deployment of this approach. Materials and methods. Cultural and virological research methods are used. Results and conclusions. Performed is the assessment of sensitivity of outbred mice, marmots and chickens to variola virus (VV) and monkeypox virus (MPV), using suspended primary cultures of lung cells (SPCLC) of these animals. Through inoculation of the mentioned above cell cultures with VV and MPV in a dose of 0.00001 PFU per a cell (plaque forming unit /cell) demonstrated has been virus replication with maximum concentration values in all cases (1,4 - 2,0 lg PFU/ml), mainly 3 days after infection. According to the data on SPCLC, sensitivity to VV in mice, marmots and chickens (ID 50 - 50 % infective dose) amounts to (1,3 ± 0,5) lg PFU; (2,3 ± 0,5) lg PFU; and (0,0 ± 0,4) lg PFU respectively, taking into account unhindered interaction of the virus with permissive lung cells in the organism of the animals. As for MPV values for this indicator, they are: (1,7 ± 0,3) lg PFU for mice, and (0,5 ± 0,3) lg PFU - for marmots. Obtained ID 50 values for VV using mice SPCLC and for MPV using mice and marmots SPCLC coincide with the ones, studied in direct experiments on intranasal infection with the viruses, with regard to 10 % of the viral application in lungs when deploying the latter method of infection. The fact testifies to the possibility of further deployment of this method for the assessment of animal sensitivity to highly pathogenic Orthopoxviruses based on the results of in vitro experiments.

Analysis of Vaccinal Process Peculiarities in Persons Immunized with Smallpox Live Vaccine in Case of Primary Vaccination and Revaccination

Натуральная оспа – особо опасное, высококонтагиозное заболевание – была ликвидирована в результате программы массового оспопрививания, инициированной ВОЗ в XX веке [3]. В настоящее время существует потенциальная опасность возрождения оспы в случае использования вируса натуральной оспы в качестве агента биотерроризма [1], и ряд стран проводит активную иммунизацию военнослужащих [10, 13]. Кроме того, возможно высвобождение вируса при проведении археологических раскопок в мерзлотных грунтах [5], а также представляют угрозу регулярно появляющиеся вспышки других ортопоксвирусных инфекций среди людей [4, 12]. Ситуация осложняется тем, что после прекращения массовой иммунизации более 30 лет назад в настоящее время около 1/3 всего населения не имеют иммунитета против оспы [3, 13]. Вакцинация остается единственным эффективным способом профилактики натуральной оспы и других ортопоксвирусных инфекций [2, 3]. Некоторые страны разрабатывают и проводят клинические испытания вакцин 3-го поколения, создают БИОТЕХНОЛОГИЯ, ИММУНОЛОГИЯ

Изучение противовирусной активности химически синтезированных соединений в отношении ортопоксвирусов в экспериментах in vitro

for ST-246 and NIOC-14 is within the range of 0,001-0,004 µg/ml, and IS for both of them is > 100000. In addition, ST-246 and NIOC-14 chemical compound efficacy, concentrated up to 0,0125; 0,025 and 0,05 µg/ml, in accordance with prophylactic charts describing an impact on ectromelia virus (EV) infectivity in vitro , is consequently 0,6; 3 and 1 lg higher than in case of compound application after an hour of Vero cells infection with EV.