Recombinant Newcastle Disease Virus Expressing a Foreign Viral Antigen Is Attenuated and Highly Immunogenic in Primates

Abstract

Paramyxoviruses such as human parainfluenza viruses that bear inserts encoding protective antigens of heterologous viruses can induce an effective immunity against the heterologous viruses in experimental animals. However, vectors based on common human pathogens would be expected to be restricted in replication in the adult human population due to high seroprevalence, an effect that would reduce vector immunogenicity. To address this issue, we evaluated Newcastle disease virus (NDV), an avian paramyxovirus that is serotypically distinct from common human pathogens, as a vaccine vector. Two strains were evaluated: the attenuated vaccine strain LaSota (NDV-LS) that replicates mostly in the chicken respiratory tract and the Beaudette C (NDV-BC) strain of intermediate virulence that produces mild systemic infection in chickens. A recombinant version of each virus was modified by the insertion, between the P and M genes, of a gene cassette encoding the human parainfluenza virus type 3 (HPIV3) hemagglutinin-neuraminidase (HN) protein, a test antigen with considerable historic data. The recombinant viruses were administered to African green monkeys (NDV-BC and NDV-LS) and rhesus monkeys (NDV-BC only) by combined intranasal and intratracheal routes at a dose of 10 6.5 PFU per site, with a second equivalent dose administered 28 days later. Little or no virus shedding was detected in nose-throat swabs or tracheal lavages following immunization with either strain. In a separate experiment, direct examination of lung tissue confirmed a highly attenuated, restricted pattern of replication by parental NDV-BC. The serum antibody response to the foreign HN protein induced by the first immunization with either NDV vector was somewhat less than that observed following a wild-type HPIV3 infection; however, the titer following the second dose exceeded that observed with HPIV3 infection, even though HPIV3 replicates much more efficiently than NDV in these animals. NDV appears to be a promising vector for the development of vaccines for humans; one application would be in controlling localized outbreaks of emerging pathogens.Paramyxoviruses have promise as vaccine vectors, particularly for intranasal immunization. For example, intranasal immunization of hamsters with a recombinant human parainfluenza virus type 3 (HPIV3) expressing the measles virus hemagglutinin protein induced a high titer of measles virusneutralizing serum antibodies (5). Immunization of hamsters with a recombinant HPIV3 expressing the hemagglutinin-neuraminidase (HN) proteins of HPIV1 and HPIV2 induced a high titer of serum antibodies against both HPIV1 and HPIV2 and induced resistance to challenge with these viruses (42). Immunization of the respiratory tract of rhesus monkeys with a recombinant attenuated bovine-human (BH) chimeric PIV3 expressing the attachment (G) and/or fusion (F) glycoprotein of human respiratory syncytial virus (RSV) induced high titers of RSV-neutralizing serum antibodies (35). Indeed, the BHPIV3 construct expressing the RSV F protein is ...

Newcastle disease virus, a host range-restricted virus, as a vaccine vector for intranasal immunization against emerging pathogens

“…In the case of the host range restriction of bovine parainfluenza virus type 3 in primates, each gene appeared to make a contribution (41). Regardless of the mechanism, it is clear that NDV is very highly restricted for replication in primates, and the level of restriction appears to be similar for the mesogenic and lentogenic pathotypes based on this work and that performed previously (31).…”

“…Two NDV vectors were evaluated. One was a recombinant copy of the mesogenic Beaudette C strain (NDV-BC) that was previously shown to be highly attenuated in non-human primates (31). The second was a recombinant copy of the lentogenic LaSota strain [which also is highly attenuated in primates (see ref.…”

“…The second was a recombinant copy of the lentogenic LaSota strain [which also is highly attenuated in primates (see ref. 31)] that was modified so that the cleavage sequence of its F protein was replaced with that of NDV-BC, resulting in the virus NDV-VF. In chickens, the imported cleavage site rendered NDV-VF capable of replication beyond the respiratory tract, resulting in a virus that is intermediate in virulence in birds compared with its lentogenic and mesogenic parents (27).…”

“…Intranasal and i.t. inoculation of AGM and rhesus monkeys with lentogenic and mesogenic strains of NDV resulted in low-level, scattered replication of the virus in the respiratory tract without any disease signs and with little or no virus shedding (31). The virus appeared to be restricted to the respiratory tract: virus was not detected in other organs or blood harvested at the peak of viral replication, and virus replication was not detected after parenteral inoculation (A.B., B.R.M., P.L.C., unpublished observations).…”

Newcastle disease virus expressing H5 hemagglutinin gene protects chickens against Newcastle disease and avian influenza

“…This result demonstrates that the degree of virulence of the recombinants expressing the HA of AIV in chickens is indistinguishable from that of the parent that represents a currently used vaccine strain. The safety of NDV recombinants expressing protective antigens of respiratory human pathogens was recently demonstrated in two species of nonhuman primates after intranasal immunization (19). These data provide evidence that a NDV-based intranasal vaccine can potentially also be developed against AIV infection in humans.…”