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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoclonal antibodies which inhibit influenza virus neuraminidase (NA) and which therefore indirectly neutralize virus infectivity bind to epitopes located on the rim of the active-site crater. The three-dimensional structure of one of these epitopes, recognized by monoclonal antibody NC41, has previously been determined (W. R. Tulip, J. N. Varghese, R. G. Webster, G. M. Air, W. G. Laver, and P. M. Colman, Cold Spring Harbor Symp. Quant. Biol. 54:257-263, 1989). Nineteen escape mutants of influenza virus A/tern/Australia/G70c/75 (N9) NA selected with NC41 were sequenced. A surprising restriction was seen in the sequence changes involved. Ten mutants had a Ser-to-Phe change at amino acid 372, and six others had mutations at position 367. No escape mutants with changes at 369 or 370 were found, although these mutations were selected with other antibodies and rendered the epitope unrecognizable by antibody NC41. Another N9 NA, from A/ruddy turnstone/NJ/85, which differs by 14 amino acids from the tern virus NA, still bound antibody NC41. Epitope mapping by selecting multiple escape mutants with antibody NC41 thus identified only three of the five polypeptide loops on NA that contact the antibody. Escape mutants selected sequentially with three different monoclonal antibodies showed three sequence changes in two loops of the NC41 epitope. The multiple mutants were indistinguishable from wild-type virus by using polyclonal rabbit antiserum in double immunodiffusion tests, but NA inhibition titers were fourfold lower. The results suggest that although the NC41 epitope contains 22 amino acids, only a few of these are so critical to the interaction with antibody that a single sequence change allows selection of an escape mutant. In that case, the variety of amino acid sequence changes which can lead to polyclonal selection of new epidemic viruses during antigenic drift might be very limited.
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PMID:Mechanism of antigenic variation in an individual epitope on influenza virus N9 neuraminidase. 170 Aug 25

The presence of mutations in the majority of the genes of cold-adapted strains A/Leningrad/134/17/57 (H2N2), A/Leningrad/134/47/57 (H2N2) and A/PR/8/59/1 (H1N1) of influenza A virus has been demonstrated by the RNA-RNA hybridization with the subsequent electrophoresis of double-stranded RNA in 7.5% polyacrylamide gel. The strains were cultivated 17, 47 and 59 passages in the chicken embryos at 25 degrees C. In the genomes of variants passaged in chicken embryos at optimal temperature of incubation 36 degrees C (hr-variants) the used technique permits identification of a single mutant gene. The obtained data suppose the attenuation of cold-adapted vaccine strains of influenza A virus and their high genetic stability to be a result of selection of the variants obtaining multiple mutations in the genome during passaging of the virions at cold temperature. The attenuation of hr-variants is defined by 1-2 mutations (first of all in HA-gene) that makes understandable their inability to serve as donors for recombinant live influenza vaccines construction.
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PMID:[Features of mutated changes of genomic RNA of cold-adapted and hr-variants of influenza group A virus, detected by RNA:RNA hybridization]. 170 66

CTLs (CD8+) are known to recognize exogenous peptide in the context of class I MHC molecules. We observed that an influenza subtype H1 and H2 cross-reactive CTL clone B7, which was stimulated by a fusion protein containing a portion of HA2 subunit of A/PR/8 virus HA, recognized a synthetic peptide (residues 515-526) of the HA2 subunit of A/PR/8 virus strain. This CTL clone also recognized a structurally disparate NS1 peptide 50-68 of the same A/PR/8 virus. We examined the recognition of the NS1 peptide 50-68 and the HA peptide 515-526 by the subcloned CTL clone, B7-B7. Cold target inhibition experiments showed that the recognition of the HA peptide by the CTL clone B7-B7 could be competed by NS1 peptide-treated target cells and vice versa. The recognition of both NS1 peptide and HA peptide by the CTL clone B7-B7 was restricted by the same allele, H2Kd. In addition, this NS1 peptide requires approximately a 600-fold higher concn for optimal CTL recognition than did the HA peptide. We conclude that the TCR on clone B7-B7 recognizes the HA peptide or the NS1 peptide as comparable complexes with the same class I MHC molecules, although there is no obvious homology in the primary sequences of HA 515-526 and NS1 50-68 peptides. CTLs elicited with certain antigens appear to recognize distinctively different antigens complexed to the same presenting MHC molecule.
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PMID:Recognition of disparate HA and NS1 peptides by an H-2Kd-restricted, influenza specific CTL clone. 170 32

T cells specific for foreign antigen recognize a complex of peptides and self-major histocompatibility complex (MHC) molecules and can also cross-react with allo-MHC molecules. It remains controversial, however, what alloreactive T cells exactly recognize. It has been proposed that alloreactive T cells recognize endogenous peptides presented by allo-MHC molecules. To test this hypothesis, we examined an influenza virus-specific T cell clone (6H5), specific for neuraminidase N2 and restricted by HLA-DR1. In the absence of influenza virus, this clone cross-reacted with HLA-DR1Dw1+ but not with HLA-DR1Dw20+ Epstein-Barr virus-transformed lymphoblastoid cells (B-LCL). Cold target inhibition experiments and the rearrangement pattern of the T cell receptor beta chain indicated that 6H5 was a monoclonal T cell population most likely using the same T cell receptor for both responses. To determine whether determinants other than HLA-DR1Dw1+ B-LCL or activated B cells, but, surprisingly, not to other cell types expressed HLA-DR1Dw1, including monocytes and transfected L cells. These experiments further support the concept that recognition of allogeneic MHC (in this case HLA-DR1Dw1) may result from a cross-reactivity of T cells specific for a complex of foreign antigen and self-MHC (neuraminidase N2 and HLA-DR1Dw20). Furthermore, allorecognition of T cell clone 6H5 appears to depend upon the recognition of a complex of allogeneic MHC and a cell-type specific endogenous peptide presented by activated B cells.
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PMID:Allo-cross-reactivity of a human neuraminidase-specific T cell clone dependent on presentation of an endogenous B cell-specific antigen. 171 May 66

Five strains of influenza viruses A(H3N2) replicated at low temperature passaged in cotton rats were reisolated. The properties of these strains replicated at low temperature were compared before and after passage in susceptible animals to check the stability of some its markers. At the same time original viruses replicated at 37 degrees C--which are different in epidemiological potency--were compared. The following parameters being tested: NA activity, HA titers, heat inactivation NA and Ha, Michaelis constants and optimum pH. We observed some differences between strains both replicated at low temperature after passage in the susceptible animal organism and original viruses from 37 degrees C. Viruses replicated at low temperature from original epidemiostrain are really cold adapted and remained stable after passage in the animals when the others derived from no epidemic strain are not stable.
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PMID:Studies on the adaptation of influenza virus replicated at low temperature. III. Biochemical studies. 171 40

Resistance against proteolysis enzymes, detergents and chemical group-specific reagents has been compared for the neuraminidase and hemagglutinin of influenza virus replicated at low temperature and original strain replicated at 37 degrees C before and after passage in the susceptible animal organism - cotton rat. Our study indicated great differences between strains and temperature conditions to resistance of the neuraminidase and hemaglutinin to proteolytic enzymes, detergens and chemical group specific reagents. No differences was found for sensitivity of influenza virus replicated at low temperature before and after passages for 3 strains -A/Pol/L/71, A/Phil/2/82, A/Pol/79/85 which are really cold adapted viruses. On the other hand neuraminidase of this strains was more resistance to these treatments.
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PMID:Studies on adaptation of influenza virus replicated at low temperature.IV. Sensitivity of neuraminidase and hemagglutinin to some proteolytic enzymes, detergents and chemical agents. 171 48

BALB/3T3 cells infected with a retroviral vector encoding the influenza virus nucleoprotein (NP) gene are efficiently lysed by CTL generated in BALB/c mice (H-2d background). Cells transduced with a mutant form of NP which contains a frameshift mutation at its NH2 terminus (NPm) do not express biochemically detectable levels of protein but nevertheless present Ag to CTL with high efficiency. Cold target inhibition studies indicate that the same CTL epitope(s) are recognized in cells harboring NP or NPm. L929 cells transduced with the NPm gene also present Ag efficiently to CTL raised in C3H mice (H-2k background). Cells engineered to express 5- to 15-fold lower levels of wild-type NP were not capable of presenting Ag to CTL, arguing against the notion that CTL are able to lyse cells expressing very low levels of Ag which might have resulted from suppression of the frameshift mutation in NPm. Implications to the mechanism of epitope generation in class I MHC-restricted immune responses are considered.
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PMID:A frameshift mutation at the NH2 terminus of the nucleoprotein gene does not affect generation of cytotoxic T lymphocyte epitopes. 171 74

Viral respiratory illnesses are among the most common afflictions in the United States. Until recently, few agents were available to control these infections. Now, there are specific and nonspecific agents either to prevent or treat viral respiratory infections. For example, a better understanding of the pathogenesis of the common cold provided new insights into therapeutic intervention for that entity. In other instances (eg, influenza), the antiviral agent is so specific that there is a need for diagnostic information to guide therapy. Epidemiological clues, clinical symptoms, and some newer laboratory methods all contribute to the clinician's understanding of the cause of an individual respiratory illness and guide the choice of therapy. In other circumstances, information is being gradually developed that points toward the availability of a broad-spectrum antiviral drug with activity against at least five of the important respiratory viruses; its major limitation is that a cumbersome and expensive means of delivery to the patient is required. For such a drug to gain widespread use, a more practical method of delivery is necessary.
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PMID:Antiviral agents in respiratory infections. 175 35

The capacity of a live influenza vaccine (LIV) to stimulate cytotoxic cells (ADCMC and NK) was studied in 49 volunteers and 56 patients with influenza. Experimental batches of LIV from influenza A and B viruses prepared by genetic recombination on the basis of cold-adapted attenuation donors were used. Type A and B LIV were shown to stimulate the cytotoxic cell-mediated and humoral immunity; the intensity of immune response, however, depended on the molecular genetic characteristics of the vaccine (genome structure, properties of the donor of attenuation), its biological activity and capacity of reproduction in tissues.
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PMID:[The formation of an immune response in volunteers inoculated with a live recombinant influenza vaccine]. 178 82

A representative sample of the Norwegian population was interviewed in 1988 as part of a monthly national opinion poll to investigate lay management and self-medication of fever. Six hundred and nineteen women and 592 men over the age of 15 were interviewed in their homes. Approximately one-fifth reported inappropriate measuring of body temperature. A variety of management and self-medication was found. In cases of common cold or influenza with fever, 35% would use antipyretics. Forty per cent would start to use antipyretics at a temperature below 39.0 degrees C. Forty-four per cent did not know any antipyretic brand names at all. The results indicate a need for more definite and consistent information to make fever management and self-medication more rational. Such information should be discussed and given by general practitioners, nurses at child welfare centers and pharmacists.
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PMID:Fever: management and self-medication. Results from a Norwegian population study. 187 61


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