Production of atypical measles in rhesus macaques: evidence for disease mediated by immune complex formation and eosinophils in the presence of fusion-inhibiting antibody

Successful DNA immunization against measles: neutralizing antibody against either the hemagglutinin or fusion glycoprotein protects rhesus macaques without evidence of atypical measles

Measles remains a principal cause of worldwide mortality, in part because young infants cannot be immunized effectively. Development of new vaccines has been hindered by previous experience with a formalin-inactivated vaccine that predisposed to a severe form of disease (atypical measles). Here we have developed and tested potential DNA vaccines for immunogenicity, efficacy and safety in a rhesus macaque model of measles. DNA protected from challenge with wild-type measles virus. Protection correlated with levels of neutralizing antibody and not with cytotoxic T lymphocyte activity. There was no evidence in any group, including those receiving hemagglutinin-encoding DNA alone, of 'priming' for atypical measles.

In vivo antibody response and in vitro CTL activation induced by selected measles vaccine candidates, prepared with purified Quil A components

Semipurified Quil A and purified Quil A were used to prepare well-characterized subunit vaccine candidates against measles. Variation in the relative amounts of the measles virus (MV) fusion (F) protein, Quil A-components and lipids did not influence induction of antibody responses in mice, but had a pronounced effect on the capacity to induce cytotoxic T cell (CTL) activity of a CD8(+) MV F-protein specific human T cell clone in vitro. A characteristic MV iscom preparation based on the combined use of HPLC-purified Quil A-components QA-3 and QA-22 (QA-3/22) efficiently induced CTL activity in vitro. Comparable results were obtained by mixing beta-propiolactone inactivated MV with iscom-matrix QA-3/22 or free QA-22. On the basis of the data presented it was concluded that these three preparations are interesting MV vaccine candidates for further evaluation in pre-clinical experiments in a primate model.

Protective immunity in macaques vaccinated with a modified vaccinia virus Ankara-based measles virus vaccine in the presence of passively acquired antibodies

Recombinant modified vaccinia virus Ankara (MVA), encoding the measles virus (MV) fusion (F) and hemagglutinin (H) (MVA-FH) glycoproteins, was evaluated in an MV vaccination-challenge model with macaques. Animals were vaccinated twice in the absence or presence of passively transferred MV-neutralizing macaque antibodies and challenged 1 year later intratracheally with wild-type MV. After the second vaccination with MVA-FH, all the animals developed MV-neutralizing antibodies and MV-specific T-cell responses. Although MVA-FH was slightly less effective in inducing MV-neutralizing antibodies in the absence of passively transferred antibodies than the currently used live attenuated vaccine, it proved to be more effective in the presence of such antibodies. All vaccinated animals were effectively protected from the challenge infection. These data suggest that MVA-FH should be further tested as an alternative to the current vaccine for infants with maternally acquired MV-neutralizing antibodies and for adults with waning vaccine-induced immunity.

Newcastle disease virus (NDV): brief history of its oncolytic strains

BACKGROUND

While genetically engineered viruses are now being tested for the virus therapy of human cancers, some naturally occurring viruses display unmatched oncolytic activity. Newcastle disease virus (NDV) excels as an oncolytic agent.

OBJECTIVES

As its virulence versus attenuation can be explained on molecular biological bases, it may be possible to develop or select highly oncolytic strains of NDV without adverse toxicity.

STUDY DESIGN

Questions are posed as to the mechanisms of viral oncolysis, the appropriateness of tests to predict oncolytic activity of a given NDV strain and the best modes of administration for oncolytic effects. Answers are provided based on specific data or on considerations drawn from experience (the authors use NDV oncolysates to immunize against melanoma and kidney carcinoma) or from analogous clinical situations (therapeutic use of mumps or measles viruses).

RESULTS AND CONCLUSIONS

NDV oncolysates probably suit better for immunotherapy (providing also active tumor-specific immunization) than massive repeated inoculations of NDV strains, especially when the NDV strain used is not proven to be oncolytic by appropriate pre-clinical tests.