Control of SIV rebound through structured treatment interruptions during early infection.

In a randomized controlled trial with acute simian immunodeficiency virus (SIV)-infected macaques, both highly active antiretroviral therapy (HAART) and HAART with fixed-schedule structured treatment interruption (STI-HAART; alternating 3 weeks on and 3 weeks off therapy) suppressed viral load. In the STI-HAART group, T cell virus-specific immune response (VIR) and control of viral rebound increased concurrently during subsequent interruptions. In contrast, VIR did not increase and SIV rebounded after permanent treatment withdrawal in all animals on continuous HAART.

Effect of PMPA and PMEA on the kinetics of viral load in simian immunodeficiency virus-infected macaques.

In this study we compared the effect of postexposure treatment of the acyclic nucleoside analogs 9-(2-phosphonylmethoxyethyl)-adenine (PMEA) and 9-(2-phosphonylmethoxypropyl)-adenine (PMPA) on the kinetics of viral load in the blood and lymph nodes of rhesus macaques chronically infected with SIVmac251 for 18 weeks. Two of the four macaques treated with PMPA (20 mg/kg per day) for 28 consecutive days had demonstrable reductions in viral loads of 1.5 and 3 logs.

Augmentation of immune responses to HIV-1 and simian immunodeficiency virus DNA vaccines by IL-2/Ig plasmid administration in rhesus monkeys.

The potential utility of plasmid DNA as an HIV-1 vaccination modality currently is an area of active investigation. However, recent studies have raised doubts as to whether plasmid DNA alone will elicit immune responses of sufficient magnitude to protect against pathogenic AIDS virus challenges. We therefore investigated whether DNA vaccine-elicited immune responses in rhesus monkeys could be augmented by using either an IL-2/Ig fusion protein or a plasmid expressing IL-2/Ig.

Aerosol infection of rhesus macaques with Junin virus.

The purpose of our work was to determine if aerosols of Junin virus can infect rhesus macaques and if the disease is the same as that produced by virus inoculated parenterally. The 6 macaques exposed to the virus by aerosol became acutely ill during the 3rd week after exposure, and all died. Three died by day 21, while the remainder died after 1 month.

Malpais spring virus: a new vesiculovirus from mosquitoes collected in New Mexico and evidence of infected indigenous and exotic ungulates.

Two virus isolates, 1 each from Aedes campestris and Psorophora signipennis mosquitoes collected in south central New Mexico in August 1985, were shown by neutralization tests to be identical to each other, but not to any of more than 250 arthropod-borne and other viruses. Electron microscopy of 1 isolate (85-488NM, chosen as the prototype) indicated that this strain shares morphologic characteristics with viruses of the family Rhabdoviridae. Indirect fluorescent antibody tests indicated that this virus is a member of the genus Vesiculovirus, but is not closely related to any of the North American or other rhabdoviruses with which it was tested, including vesicular stomatitis (Indiana) and vesicular stomatitis (New Jersey) viruses.

Antibody response of sandhill and whooping cranes to an eastern equine encephalitis virus vaccine.

As a possible strategy to protect whooping cranes (Grus americana) from fatal eastern equine encephalitis (EEE) viral infection, studies were conducted to determine the immune response of this species and sandhill cranes (Grus canadensis) to a formalin-inactivated EEE viral vaccine. Viral-specific neutralizing antibody was elicited in both species after intramuscular (IM) vaccination. Subcutaneous and intravenous routes of vaccination failed to elicit detectable antibody in sandhill cranes.

Identification of Aedes campestris from New Mexico: with notes on the isolation of western equine encephalitis and other arboviruses.

An arbovirus survey was conducted during August 1985 at White Sands Missile Range in southcentral New Mexico following a suspected arboviral disease epizootic among feral horses. A total of 20,566 mosquitoes (18,505 females and 2,061 males) and 8,900 biting gnats were collected and assayed for virus. Female mosquitoes were principally Aedes campestris (54.

Mortality of captive whooping cranes caused by eastern equine encephalitis virus.

Of 39 captive whooping cranes (Grus americana), 7 died during a 7-week period (Sept 17 through Nov 4, 1984) at the Patuxent Wildlife Research Center, Laurel, Md. Before their deaths, 4 cranes did not develop clinical signs, whereas the other 3 cranes were lethargic and ataxic, with high aspartate transaminase, gamma-glutamyl transferase, and lactic acid dehydrogenase activities, and high uric acid concentrations. Necropsies indicated that the birds had ascites, intestinal mucosal discoloration, fat depletion, hepatomegaly, splenomegaly, and visceral gout.

Absence of La Crosse virus in the presence of Aedes triseriatus on the Delmarva Peninsula.

Between 1980 and 1984, field studies were conducted in 2 areas on the Delmarva Peninsula to identify the presence of La Crosse (LAC) virus. Ovitraps were used to collect eggs of Aedes triseriatus complex mosquitoes. No virus was obtained from 969 pools containing 22,370 adult mosquitoes reared from eggs.

Glucan-induced enhancement of host resistance to selected infectious diseases.

We conducted studies with mice, rats, and monkeys which demonstrated the ability of glucan to induce either nonspecific or specific enhancement of host resistance to infectious diseases. Intravenous pretreatment of mice with glucan significantly enhanced the survival of mice challenged with either Venezuelan equine encephalomyelitis (VEE) virus or Rift Valley fever virus. Pretreatment was beneficial when initiated 3 days before challenge with VEE virus and 7 days before challenge with Rift Valley fever virus.

Evaluation of a formalin-inactivated Rift Valley fever vaccine in sheep.

A formalin-inactivated Rift Valley fever (RVF) vaccine prepared in cell culture for human use was immunogenic in sheep. Vaccine was administered as a single dose of diluted (1:5) or undiluted vaccine with or without an adjuvant. Serum-neutralizing antibodies induced by RVF vaccine persisted for at least 7 months.

Adjuvant activity of a novel metabolizable lipid emulsion with inactivated viral vaccines.

Studies were conducted in mice, hamsters, sheep, and two species of nonhuman primates which demonstrate the adjuvant activity of a new metabolizable lipid emulsion with marginally immunogenic doses of Formalin-inactivated viral vaccines. The lipid base consists of highly refined peanut oil emulsified in aqueous vaccines with glycerol and lecithin. Hamsters and mice inoculated with lipid emulsion plus western or Venezuelan equine encephalitis vaccine were significantly more resistant than vaccinated controls to lethal homologous virus challenge.

Adjuvant effects of low doses of a nuclease-resistant derivative of polyinosinic acid . polycytidylic acid on antibody responses of monkeys to inactivated Venezuelan equine encephalomyelitis virus vaccine.

Polyriboinosinic.polyribocytidylic acid [poly(I).poly(C)] stabilized with poly-l-lysine and carboxymethylcellulose [poly(ICLC)] has been previously shown to be a compound with marked adjuvant activity when given in high doses with inactivated Venezuelan equine encephalomyelitis (VEE) virus vaccine.

Inactivated Venezuelan equine encephalomyelitis virus vaccine complexed with specific antibody: enhanced primary immune response and altered pattern of antibody class elicited.

Complexes of formalinized Venezuelan equine encephalomyelitis (VEE) virus vaccine and specific IgG formed at antigen-antibody equivalence enhanced the immune responses of rhesus monkeys (Macaca mulatta). The predomonant class of antibody elicited by complexes was IgG. In contrast, lower titers of antibody and a more biphasic (IgG-IgM) response were observed after exposure of monkeys to the vaccine alone.

Modified polyriboinosinic-polyribocytidylic acid, an immunological adjuvant.

Stabilization of polyriboinosinic-polyribocytidylic acid against enzymatic hydrolysis by addition of poly-1-lysine and carboxymethylcellulose (PICLC) resulted in a compound with marked adjuvanticity. The primary antibody response of rhesus monkeys to formalin-inactivated Venezuelan equine encephalomyelitis virus vaccine was significantly potentiated if the vaccine was combined with PICLC prior to vaccination. The antibody response was maintained at a significantly higher level than controls for 2.

Adjuvant effects of diethylaminoethyl-dextran.

Diethylaminoethyl-dextran exhibited a significant effect on the primary immune response of rhesus monkeys to formalin-inactivated Venezuelan equine encephalomyelitis virus vaccine (IVEE). Antibody formed to IVEE and adjuvant followed a classic immunoglobulin M-immunoglobulin G pattern; however, as compared with vaccine alone, use of this adjuvant with IVEE reduced the time required for onset of immunoglobulin G synthesis.

Transplacental transmission of Venezuelan equine encephalomyelitis virus in mice.

Transplacental infection of mouse fetuses with Venezuelan equine encephalomyelitis was produced by intraperitoneal injection of dams at various stages of gestation with 10(3) suckling mouse intracerebral median lethal doses of an attenuated strain (TC-83). Virus inoculation, at times ranging from 6 days prior to mating to 9 days after conception, had no effect on conception rate, litter size, or survival of the newborn. Inoculation of the dam from the 10th to 13th days of gestation resulted in decreased litter size, an increase in stillbirths, and a decrease in birth-to-weaning survival.