A single donor is sufficient to produce a highly functional in vitro antibody library.

Antibody complementarity determining region diversity has been considered to be the most important metric for the production of a functional antibody library. Generally, the greater the antibody library diversity, the greater the probability of selecting a diverse array of high affinity leads. According to this paradigm, the primary means of elevating library diversity has been by increasing the number of donors.

Influenza immunization elicits antibodies specific for an egg-adapted vaccine strain.

For broad protection against infection by viruses such as influenza or HIV, vaccines should elicit antibodies that bind conserved viral epitopes, such as the receptor-binding site (RBS). RBS-directed antibodies have been described for both HIV and influenza virus, and the design of immunogens to elicit them is a goal of vaccine research in both fields. Residues in the RBS of influenza virus hemagglutinin (HA) determine a preference for the avian or human receptor, α-2,3-linked sialic acid and α-2,6-linked sialic acid, respectively.

Mutations in the membrane-proximal region of the influenza A virus M2 protein cytoplasmic tail have modest effects on virus replication.

Influenza A virus encodes M2, a proton channel that has been shown to be important during virus entry and assembly. In order to systematically investigate the role of the membrane-proximal residues in the M2 cytoplasmic tail in virus replication, we utilized scanning and directed alanine mutagenesis in combination with transcomplementation assays and recombinant viruses. The membrane-proximal residues 46 to 69 tolerated numerous mutations, with little, if any, effect on virus replication, suggesting that protein structure rather than individual amino acid identity in this region may be critical for M2 protein function.

The influenza C virus CM2 protein can alter intracellular pH, and its transmembrane domain can substitute for that of the influenza A virus M2 protein and support infectious virus production.

The influenza C virus CM2 protein and a chimeric influenza A virus M2 protein (MCM) containing the CM2 transmembrane domain were assessed for their ability to functionally replace the M2 protein. While all three proteins could alter cytosolic pH to various degrees when expressed from cDNA, only M2 and MCM could at least partially restore infectious virus production to M2-deficient influenza A viruses. The data suggest that while the CM2 ion channel activity is similar to that of M2, sequences in the extracellular and/or cytoplasmic domains play important roles in infectious virus production.

The cholesterol recognition/interaction amino acid consensus motif of the influenza A virus M2 protein is not required for virus replication but contributes to virulence.

Influenza A virus particles assemble and bud from plasma membrane domains enriched with the viral glycoproteins but only a small fraction of the total M2 protein is incorporated into virus particles when compared to the other viral glycoproteins. A membrane proximal cholesterol recognition/interaction amino acid consensus (CRAC) motif was previously identified in M2 and suggested to play a role in protein function. We investigated the importance of the CRAC motif on virus replication by generating recombinant proteins and viruses containing amino acid substitutions in this motif.

Human antibodies reveal a protective epitope that is highly conserved among human and nonhuman influenza A viruses.

Influenza remains a serious public health threat throughout the world. Vaccines and antivirals are available that can provide protection from infection. However, new viral strains emerge continuously because of the plasticity of the influenza genome, which necessitates annual reformulation of vaccine antigens, and resistance to antivirals can appear rapidly and become entrenched in circulating virus populations.

Tyrosines in the influenza A virus M2 protein cytoplasmic tail are critical for production of infectious virus particles.

The cytoplasmic tail of the influenza A virus M2 protein is required for the production of infectious virions. In this study, critical residues in the M2 cytoplasmic tail were identified by single-alanine scanning mutagenesis. The tyrosine residue at position 76, which is conserved in >99% of influenza virus strains sequenced to date, was identified as being critical for the formation of infectious virus particles using both reverse genetics and a protein trans-complementation assay.

Presence of broadly reactive and group-specific neutralizing epitopes on newly described isolates of Crimean-Congo hemorrhagic fever virus.

Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the genus Nairovirus of the family Bunyaviridae, causes severe disease in humans with high rates of mortality. The virus has a tripartite genome composed of a small (S), a medium (M) and a large (L) RNA segment; the M segment encodes the two viral glycoproteins, G(N) and G(C). Whilst relatively few full-length M segment sequences are available, it is apparent that both G(N) and G(C) may exhibit significant sequence diversity.