Studies of passive immunotherapy for infections of respiratory syncytial virus in the respiratory tract of a primate model.
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Animals↗
Biomedical subjects
B R Murphy
Publications and source records attributed to B R Murphy.
Development of subtype-specific and heterosubtypic antibodies to the influenza A virus hemagglutinin after primary infection in children.
Children undergoing primary infection with an H1N1 or H3N2 influenza A virus developed subtype-specific hemagglutination inhibition antibodies and enzyme-linked immunosorbent assay antibodies to purified hemagglutinin (HA) of the infecting virus subtype. They also developed lower titered ELISA antibodies to the noninfecting H1 or H3 HA and to H8 (an avian strain) HA. Thus, after primary infection with an influenza A virus, children develop enzyme-linked immunosorbent assay, but not hemagglutination inhibition, antibodies reactive with heterosubtypic HAs. These heterosubtypic antibodies could influence the response to infection with other wild-type or attenuated vaccine strains of influenza A virus.
Antibodies, Heterophile↗
Response of seronegative and seropositive adult volunteers to live attenuated cold-adapted reassortant influenza A virus vaccine.
The infectivity and immunogenicity of live attenuated A/Washington/897/80 cold-adapted reassortant virus vaccine was evaluated in seronegative (hemagglutination inhibition titer, less than or equal to 1:4) and seropositive (hemagglutination inhibition titer, greater than 1:4) adult volunteers. The vaccine was efficient in infecting seronegative volunteers (94%). Moreover, 51% of seropositive vaccinees were infected by the virus. After live virus vaccination, greater than 83% of both seronegative and seropositive vaccinees achieved a level of nasal wash antibody previously associated with resistance to infection with influenza A virus. These findings indicate that both seronegative and seropositive vaccinees can benefit from live virus vaccination.
Adolescent↗
Subclass distribution and molecular form of immunoglobulin A hemagglutinin antibodies in sera and nasal secretions after experimental secondary infection with influenza A virus in humans.
Serum and nasal wash specimens from 13 human volunteers undergoing experimental secondary infection with influenza A/Peking/2/79 (H3N2) wild-type virus were examined for the molecular form and subclass distribution of immunoglobulin A (IgA) antibodies to the viral hemagglutinin (HA). Nasal IgA antibodies were polymeric and did not bind radiolabeled secretory component, indicating that they were secretory IgA antibodies. Both IgA1 and IgA2 antibodies were detected; however, IgA1 accounted for most of the rise in IgA anti-HA levels seen after infection. In serum virtually all of the IgA HA antibodies were of the IgA1 subclass. Furthermore, the serum antibodies were predominantly polymeric and were capable of binding radiolabeled secretory component. These results suggested that the serum IgA antibodies to HA were of mucosal origin and that influenza A virus HA preferentially stimulates an IgA1 response.
Hemagglutinins↗
Attenuation of wild-type human influenza A virus by acquisition of the PA polymerase and matrix protein genes of influenza A/Ann Arbor/6/60 cold-adapted donor virus.
Wild-type influenza A viruses can be attenuated for humans by the acquisition of genes from the A/Ann Arbor/6/60 cold-adapted (ca) donor virus. Six-gene reassortants, that is, viruses containing the hemagglutinin and neuraminidase surface glycoprotein genes of the wild-type virus and the six remaining RNA segments of the ca donor virus, are consistently attenuated for humans. During the production of a six-gene reassortant virus containing the surface glycoproteins of the A/Washington/897/80 (H3N2) wild-type virus, a reassortant virus was isolated that contained RNA segments 3 (coding for the polymerase PA protein) and 7 (coding for matrix [M] proteins) from the ca parent and all other genes from the wild-type virus. This reassortant virus is referred to as a two-gene reassortant. Because the gene or set of genes responsible for the attenuation of ca reassortant viruses has not been defined, we evaluated the two-gene reassortant for level of replication and level of virulence in ferrets and in humans, and we compared its characteristics to those of a six-gene reassortant virus derived from the same two parents. The two-gene reassortant virus infected each of 14 adult seronegative (serum hemagglutination inhibition titer of less than or equal to 1:8) volunteers when administered intranasally at a dose of 10(7) 50% tissue culture infectious doses, yet it did not produce illness. The level of replication of the two-gene reassortant virus in the upper respiratory tract was equivalent to that of the six-gene reassortant virus. This demonstrates that transfer of the A/Ann Arbor/6/60 ca PA polymerase and M genes is sufficient to confer the attenuation phenotype on wild-type influenza A viruses. In the context of previous observations, these results suggest that the A/Ann Arbor/6/60 ca donor virus PA polymerase gene plays a major role in the attenuation of ca reassortant viruses.
Animals↗
Nucleoprotein and membrane protein genes are associated with restriction of replication of influenza A/Mallard/NY/78 virus and its reassortants in squirrel monkey respiratory tract.
An avian influenza A virus, A/Mallard/NY/6750/78(H2N2), was restricted in in replication in the respiratory tract of squirrel monkeys. Avian-human influenza A reassortant viruses possessing the six RNA segments coding for nonsurface proteins (i.e., internal genes) of this avian virus were as restricted in replication in squirrel monkeys as their avian influenza parent. These findings indicated that restriction of replication of the avian influenza virus is a function of one or more of its internal genes. For an investigation of which of the avian influenza genes was responsible for restricted replication in the respiratory tract of primates, reassortant viruses were produced that contained human influenza virus surface antigens from the A/Udorn/72(H3N2) virus and one or more of the internal genes derived from the avian influenza virus parent. Avian-human reassortant influenza A viruses containing only the nucleoprotein or matrix protein RNA segment from the avian influenza virus parent were as restricted in their growth as an avian-human influenza reassortant virus containing each of the six avian influenza internal genes. In addition, an avian-human influenza reassortant virus possessing only the avian RNA 1 and nonstructural genes (which by themselves do not specify restricted replication) manifested a significant reduction of virus replication in squirrel monkey tracheas. Thus, the avian nucleoprotein and matrix genes appear to play a major role in the host range restriction exhibited by the A/Mallard/78 virus and its reassortants, but the combination of RNA 1 and nonstructural genes also contributes to restriction of replication.
Animals↗
Advantage of live attenuated cold-adapted influenza A virus over inactivated vaccine for A/Washington/80 (H3N2) wild-type virus infection.
The efficacy of live attenuated cold-adapted (ca) reassortant influenza virus vaccine against experimental challenge with homologous wild-type virus 5 to 8 weeks after vaccination was compared with that of licensed inactivated vaccine in 81 seronegative (haemagglutination-inhibition antibody titre less than or equal to 1:8) college students. At a dose of 10(7.5) 50% tissue culture infectious dose (TCID50) (70 HID50, human 50% infectious doses) the live virus vaccine, given intranasally, completely protected against illness caused by wild-type virus, whereas the inactivated vaccine, administered intramuscularly, provided 72% protection. Wild-type virus was recovered from only 13% of live virus vaccinees (10(7.5) TCID50 dose of ca virus) compared with 63% of inactivated virus vaccinees and the few infected live virus vaccinees shed 1000 times less wild-type virus than did infected inactivated virus vaccinees or unvaccinated controls. This striking reduction in virus shedding suggests that influenza transmission may be more efficiently interrupted with live than with inactivated virus vaccination.
Administration, Intranasal↗
Characterization of the genotype and level of attenuation of an influenza A reassortant virus produced by mating the Xia-ts donor virus with A/Beijing/70 (H1N1) wild type virus.
Two H1N1 progeny viruses derived by mating the attenuated donor virus, the A/Ningxia/72-ts (H3N2), and the A/Beijing/70 (H1N1) wild type virus were characterized for their genotype and their level of attenuation in susceptible adult volunteers. One progeny virus, clone PX62, was not a reassortant since it received each of its eight RNA segments from the H1N1 wild type virus. THis virus caused febrile influenza illness. Another progeny virus, clone PXH107, was a reassortant which received the genes coding for the surface antigens from the H1N1 parent virus but each of the other six RNA segments from the H3N2 parent virus. This clone was satisfactorily attenuated in susceptible adults and induced an immune response in at least 60% of the vaccinees. These results indicate that the genetic determinants of attenuation of the A/Ningxia/72-ts virus reside on one or more of the RNA segments that do not code for the surface antigens.
Adolescent↗
Dose response of influenza A/Washington/897/80 (H3N2) cold-adapted reassortant virus in adult volunteers.
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Adult↗
Dose response of cold-adapted, reassortant influenza A/California/10/78 virus (H1N1) in adult volunteers.
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Adult↗
Avian-human reassortant influenza A viruses derived by mating avian and human influenza A viruses.
Reassortant influenza A viruses were produced by mating an avian virus (A/Mallard/NY/78, A/Mallard/Alberta/78, or A/Pintail/Alberta/79) with a wild-type human influenza A virus. From each mating a reassortant virus was obtained that contained the genes coding for the hemagglutinin and neuraminidase surface antigens of the human influenza A wild-type virus and the six other RNA segments ("internal genes") of the avian influenza A virus parent. The avian-human reassortant influenza viruses produced resembled their avian virus parent in that they produced plaques on MDCK monolayers at 42 C, a temperature restrictive for the human influenza viruses. In the trachea of squirrel monkeys, each avian-human reassortant influenza virus was as restricted in its replication as was its avian influenza virus parent. Thus, one or more of the six internal genes of each avian parent virus was responsible for restriction of the reassortant virus in monkeys. The A/Washington/80 X A/Mallard/NY/78 reassortant virus retained its phenotype of restricted replication in monkeys after five serial passages in vivo. It also failed to transmit to cagemates or induce resistance to wild-type virus challenge, and it did not initiate a systemic or enteric infection. These findings form the basis for evaluation of these attenuated avian-human reassortant influenza A viruses as live attenuated vaccines for humans.
Animals↗
Antigenic characterization of influenza A virus matrix protein with monoclonal antibodies.
Monoclonal antibodies were used to study antigenic variation in three distinct epitopes on the matrix protein of influenza A viruses. We found that two of these epitopes underwent antigenic variation, but in a very limited number of virus strains. A third epitope appeared to be an invariant type-specific determinant for influenza A viruses. Competitive antibody binding assays and Western blot analysis of proteolytically digested matrix protein indicated that at least two of the three epitopes are located in nonoverlapping domains on the matrix protein molecule.
Antibodies, Monoclonal↗
Altered tissue tropism of human-avian reassortant influenza viruses.
Avian influenza viruses replicate to high titers in the cells lining the intestinal tract of birds; however, human strains do not. A series of reassortant viruses with all six internal genes from an avian strain and one or both genes for the surface antigens from a human strain failed to transit and infect the intestinal tracts of ducks. However, these reassortants did replicate in the bursa of ducks after rectal inoculation. These studies provide the first evidence that the hemagglutinin and neuraminidase are critical for the enterotropism of avian viruses but are not essential for replication in other avian tissues.
Animals↗
Temperature-sensitive mutants of influenza A/Udorn/72 (H3N2) virus. III. Genetic analysis of temperature-dependent host range mutants.
One hundred thirty-three ts mutants of influenza A/Udorn/72 virus were arranged into eight complementation groups, A-H, on Madin-Darby canine kidney (MDCK) monolayer cultures at the restrictive temperature of 40 degrees. The eight complementation groups, A-H, on MDCK cells corresponded to the eight recombination groups, A-H, on rhesus monkey kidney (RMK) cells, respectively, and this suggested that each MDCK complementation group represented one of the eight influenza A RNA gene segments. These ts viruses were used to identify the locus of the ts mutation in temperature-dependent host range (td-hr) mutants of the A/Udorn/72 virus. Sixteen of the 133 ts mutants exhibited distinct host (MDCK)-dependent restriction of plaque formation at 40 degrees but not at 34 degrees and were referred to as td-hr mutants. These 16 td-hr mutants were ts+ (not ts) on RMK cells but ts on MDCK cells. The td-hr mutants did not share a common lesion and the ts lesions were distributed among the eight complementation groups, A-H, when tested on MDCK cells. An analysis of one of the td-hr mutants indicated that an extrageneic RMK-dependent suppressor mutation did not account for the td-hr phenotype. These data suggested that a host-dependent ts mutation was responsible for the td-hr restriction of this mutant. Representation of td-hr mutations in each of the eight complementation groups indicates that the influenza A virus genome can undergo mutation leading to an altered host range in any of its eight RNA segments.
Animals↗
Construction and characterization of an infectious vaccinia virus recombinant that expresses the influenza hemagglutinin gene and induces resistance to influenza virus infection in hamsters.
A DNA copy of the influenza virus hemagglutinin gene, derived from influenza virus A/Jap/305/57 (H2N2) was inserted into the genome of vaccinia virus under the control of an early vaccinia virus promoter. Tissue culture cells infected with the purified recombinant virus synthesized influenza hemagglutinin, which was glycosylated and transported to the cell surface where it could be cleaved with trypsin into HA1 and HA2 subunits. Rabbits and hamsters inoculated intradermally with recombinant virus produced circulating antibodies that inhibited hemagglutination by influenza virus. Furthermore, vaccinated hamsters achieved levels of antibody similar to those obtained upon primary infection with influenza virus and were protected against respiratory infection with the A/Jap/305/57 influenza virus.
Animals↗
Dose response of A/Alaska/6/77 (H3N2) cold-adapted reassortant vaccine virus in adult volunteers: role of local antibody in resistance to infection with vaccine virus.
An attenuated influenza A candidate vaccine virus, derived from the A/Ann Arbor/6/60 (H2N2) cold-adapted (ca) donor virus and the A/Alaska/6/77 (H3N2) wild-type virus, was evaluated in adult seronegative volunteers (serum hemagglutination-inhibiting antibody titer, less than or equal to 1:8) for level of attenuation, infectivity, antigenicity, and genetic stability. Four groups with similar preinoculation mean titers of serum and nasal wash antibodies were inoculated intranasally with 10(4.5), 10(5.5), 10(6.5), or 10(7.5) 50% tissue culture infectious doses (TCID50) of the ca reassortant virus, and eight other seronegative adult volunteers received the wild-type virus. Only 2 of 66 vaccinees developed fever or mild and brief systemic or upper respiratory tract illness or both. Both volunteers with vaccine-related reactions received the highest dose (10(7.5) TCID50) of ca virus, which indicates that the vaccine retains some mild reactogenicity at a high dosage. In contrast, four of eight volunteers infected with the wild-type virus became ill. Each of the 54 isolates tested retained the temperature-sensitive phenotype of the vaccine virus. Thus, the ca reassortant was genetically stable and attenuated at 10(4.5) to 10(7.5) TCID50 for seronegative adults. The 50% human infective dose of ca virus was approximately 10(5.3) TCID50. Ten and one hundred 50% human infectious doses infected 73 and 83% of vaccinees, respectively, and approximately 75% developed an immunological response at these doses. The failure of the vaccine virus to infect some volunteers was correlated with the presence of pre-inoculation nasal wash immunoglobulin A hemagglutinin antibody.
Adult↗
Secretory immunological response after intranasal inactivated influenza A virus vaccinations: evidence for immunoglobulin A memory.
An intranasal, inactivated trivalent influenza A vaccine containing 7 micrograms of A/Bangkok/1/79 (H3N2) hemagglutinin was administered to 20 children aged 1 to 6 years to assess the local and systemic immune responses to antigen delivered to the respiratory tract. Six children without prior influenza virus infection exhibited no local immune response and manifested only a minimal systemic response to the intranasal vaccine. In contrast, five individuals who were previously infected with a live attenuated influenza A H3N2 virus vaccine, although having no residual secretory antibody at the time of challenge, promptly developed a local antibody response to intranasal, inactivated antigen. Therefore, the live influenza A virus vaccine had induced memory in the local immunoglobulin A (IgA) immune system. The third group of nine children had previously been infected with wild-type H3N2 influenza virus. A majority of these children had residual local and systemic antibody at the time of challenge but they demonstrated some boosting of local IgA antibody with administration of intranasal inactivated vaccine. The competence of the secretory IgA immune system in young children in mounting primary and secondary responses to influenza antigens has important implications for approaches to prevention of influenzal illness.
Administration, Intranasal↗
Hemagglutinin-specific antibody responses in immunoglobulin G, A, and M isotypes as measured by enzyme-linked immunosorbent assay after primary or secondary infection of humans with influenza A virus.
The isotype-specific antibody responses to purified hemagglutinin of adults undergoing either primary or secondary infection with an influenza A virus were characterized by using an enzyme-linked immunosorbent assay. Twenty-eight military recruits undergoing primary infection with A/USSR/92/77 (H1N1)-like virus had serum antibody rises in the immunoglobulin M (IgM) (86%), IgG (100%), and IgA (96%) isotypes. In contrast, 19 adult volunteers undergoing secondary infection with A/Peking/2/79 (H3N2) wild-type virus had serum antibody titer rises largely restricted to the IgG (68%) and IgA (74%) classes, with only 1 volunteer having a serum IgM antibody titer rise. Nasal wash hemagglutinin-specific antibody responses in the adults undergoing secondary infection were predominantly in the IgA class (74%). There was a correlation between the presence of and the magnitude of nasal wash and serum hemagglutinin-specific IgA antibody responses in these adults. This suggested that there was a common source for the hemagglutinin-specific local IgA antibody and serum IgA antibody produced after infection. The recruits undergoing primary H1N1 influenza virus infection had H1 hemagglutinin-specific enzyme-linked immunosorbent assay antibody in each of the IgA, IgG, and IgM isotypes in their acute-phase serum. However, no role for this cross-reactive antibody in modifying the severity of illness experienced by the recruits could be demonstrated.
Adult↗