This new H1N1 strain is sufficiently distinct, for example, from the A/Brisbane/59/2007 (H1N1)-like virus strain of influenza in the 2008/09 Northern hemisphere vaccine that

protection is not expected to be substantial. The human immune system responds primarily to the five epitope regions of the hemagglutinin protein. By determining the fraction of amino acids that differ between a vaccine strain and a viral challenge strain in the dominant epitope regions, a measure of antigenic distance that correlates with epidemiological studies of H3 influenza A vaccine efficacy in humans with R(2) = 0.81 is derived. This measure of antigenic distance is called p(epitope). click here The relation between vaccine efficacy and p(epitope) is given by E = 0.47 – 2.47 x p(epitope). We here identify the epitope regions of H1 hemagglutinin, so that vaccine efficacy may be reliably estimated for H1N1 influenza A.”
“Polychlorinated biphenyls (PCBs) are developmental neurotoxicants that

produce cognitive and behavioral changes in children exposed during gestation and lactation. Coplanar PCBs bind the aryl hydrocarbon receptor (AHR) and can be sequestered in liver by cytochrome P450 1A2 (CYP1A2). The AHR is a ligand-activated this website transcription factor which increases expression of the CYP1 family, including CYP1A2. Our previous work examining genetic susceptibility to developmental PCB neurotoxicity showed that Ahr(b)Cyp1a2(-/-) mice with the high-affinity Ahr(b) allele and lacking CYP1A2 were most susceptible while Ahr(b)Cyp1a2(+/+) and poor-affinity Ahr(d)Cyp1a2(+/+) mice were resistant. To follow up, a fourth line

of mice was generated with the Ahr(d)Cyp1a2(-/-) genotype and compared with the background strain Ahr(b)Cyp1a2(+/+). Dams received a PCB mixture or the corn oil vehicle at gestational Day 10(GD10) and postnatal Day 5 (PND5). Offspring were tested at PND60 in open field locomotor, acoustic startle with pre-pulse inhibition (PPI), novel object recognition and Morris water maze. Locomotor activity was increased in PCB-treated Ahr(b)Cyp1a2(+/+) mice, but no differences were seen in control vs. pheromone PCB-treated Ahr(d)Cyp1a2(-/-) mice. PCB-treated Ahr(d)Cyp1a2(-/-) mice had a higher baseline startle response and significantly reduced pre-pulse inhibition at the 74 dB level compared with corn oil-treated controls (P < 0.05). PCB-treated Ahr(d)Cyp1a2(-/-) mice had impairments in novel objective recognition (P < 0.05) and during all three hidden platform phases of Morris water maze (P < 0.01). Combined with our previous findings, these results indicate Cyp1a2 genotype is more important in susceptibility to PCB-induced deficits in learning and memory, but Ahr genotype appears more important when assessing acoustic startle-PPI and locomotor activity. (C) 2012 Elsevier Inc. All rights reserved.