Pandemic H1N1 Influenza Infection and Vaccination in Humans Induces Cross-Protective Antibodies that Target the Hemagglutinin Stem

Most monoclonal antibodies (mAbs) generated from humans infected or vaccinated with the 2009 pandemic H1N1 (pdmH1N1) influenza virus targeted the hemagglutinin (HA) stem. These anti-HA stem mAbs mostly used IGHV1-69 and bound readily to epitopes on the conventional seasonal influenza and pdmH1N1 vaccines. The anti-HA stem mAbs neutralized pdmH1N1, seasonal influenza H1N1 and avian H5N1 influenza viruses by inhibiting HA-mediated fusion of membranes and protected against and treated heterologous lethal infections in mice with H5N1 influenza virus. This demonstrated that therapeutic mAbs could be generated a few months after the new virus emerged. Human immunization with the pdmH1N1 vaccine induced circulating antibodies that when passively transferred, protected mice from lethal, heterologous H5N1 influenza infections. We observed that the dominant heterosubtypic antibody response against the HA stem correlated with the relative absence of memory B cells against the HA head of pdmH1N1, thus enabling the rare heterosubtypic memory B cells induced by seasonal influenza and specific for conserved sites on the HA stem to compete for T-cell help. These results support the notion that broadly protective antibodies against influenza would be induced by successive vaccination with conventional influenza vaccines based on subtypes of HA in viruses not circulating in humans.

Immunogenicity of a half-dose of adjuvanted 2009 pandemic H1N1 influenza vaccine in adults: a prospective cohort study

We aimed to assess the immunogenicity of a single half-dose of AS03-adjuvanted monovalent 2009 pandemic H1N1 vaccine in healthy adults. Healthy subjects age 20-60 years were prospectively enrolled in a cohort receiving intramuscular administration of a single half-dose (1.875 μg of hemagglutinin [HA]) of adjuvanted 2009 pandemic H1N1 influenza vaccine. Data from participants enrolled in a concomitant study of immunogenicity following a full-dose (3.75 μg of HA) are presented concurrently. Sera for assessment of hemagglutination-inhibiting (HAI) antibody to the vaccine strain were obtained before and 14 or 21 days after vaccination. Ninety-seven participants received a half-dose and 50 received a full-dose of vaccine. In the half-dose cohort, Food and Drug Administration criteria for immunogenicity regarding seroprotection and seroconversion rates were met for subjects aged 20-45 years, but not for those aged 46-60 years. There was no statistically significant difference in the proportion of individuals achieving a post-vaccination HAI titre of ≥1:40, the geometric mean titres of post-vaccination antibody, or the proportion of individuals with a four-fold or greater increase in antibody levels between the two cohorts. Participants 46-60 years of age were significantly less likely to be seroprotected at day 21 than those 20-45 years old in both cohorts. Immunogenicity of a half dose of adjuvanted pH1N1 influenza vaccine was adequate in subjects aged 20-45 years. Dose reduction is a possible strategy for expanding the availability in the event of vaccine shortage in this age group.

Changing patterns of gene expression identify multiple steps during regression of rat prostate in vivo

The rat ventral prostate is an androgen-dependent organ that undergoes dramatic cell death upon removal of testosterone by surgical castration. Several well characterized criteria, such as nuclear condensation, organelle blebbing, and DNA fragmentation, have been used to demonstrate that most of this cell loss is due to programmed cell death, or apoptosis, of the secretory epithelial cells. In addition to changes in morphology, it is well known that cells undergoing apoptosis show alterations in gene expression, and it is widely assumed that many of these genes are directly involved in the mechanism of programmed cell death. Using poly A+ RNA derived from normal rat prostate as well as from the regressing prostates of castrated rats, we have used a PCR-based subtractive hybridization approach to generate complementary DNA (cDNA) libraries greatly enriched in cDNAs strongly regulated during rat prostate regression. Several hundred of the genes represented in these libraries appear to be strongly regulated during prostate regression and most of these are prostate specific. Sequence analysis indicates that up to 30% of these clones are similar or identical to genes of known function, approximately 20% are similar to expressed sequence tags (ESTs), and as many as 50% of these clones have not been characterized previously. Analysis of selected clones using in situ hybridization indicates that they are expressed specifically in prostate epithelial cells, and that certain of these clones are regulated temporally in a pattern consistent with apoptosis. The patterns of gene expression include: 1) genes whose expression decreases uniformly after removal of androgen, indicative of androgen sensitive genes; 2) genes whose expression increases in apoptotic prostate cells and in other tissues, suggesting a class of genes generally involved in apoptosis; 3) and genes whose expression increases in individual regressing prostate epithelial cells, suggesting a class of prostate specific genes associated with apoptosis.

The lurcher gene induces apoptotic death in cerebellar Purkinje cells

In the neurologically mutant mouse strain lurcher (Lc), heterozygous animals display cell autonomous degeneration of cerebellar Purkinje cells beginning in the second postnatal week. During the course of our studies to identify the genetic lesion responsible for this disease (Norman et al., 1991), we have formulated an hypothesis suggesting that in Lc Purkinje cells homeostasis is sufficiently perturbed to lead to the activation of programmed cell death, thus resulting in neuronal loss and the consequent neurologic disease (Heintz, 1993). To address this possibility, we have examined the properties of Lc Purkinje cells as they die during the second postnatal week. Our light and electron microscopic studies demonstrate that dying Lc Purkinje cells exhibit the characteristic morphologic features of apoptosis, including nuclear condensation, axon beading and membrane blebbing. Using an in situ end-labeling method, we have also detected nicked nuclear DNA in these cells. Furthermore, we have examined the expression of the sulfated glycoprotein 2 (SGP2), whose mRNA is induced in both T-cells and prostate epithelial cells undergoing apoptotic death. We show by in situ hybridization that SGP2 is not expressed at detectable levels in normal Purkinje cells, but that its mRNA is present in Lc Purkinje cells prior to their death. Also expression of the Kv3.3b potassium channel, which marks the terminal phase of Purkinje cell differentiation, is evident in Lc Purkinje cells prior to their death. These data demonstrate that the Lc mutation induces apoptosis in cerebellar Purkinje cells following their maturation in postnatal cerebellum. Isolation of the Lc mutation and further analysis of its action in eliciting apoptosis can provide an important opportunity for understanding the etiology of neurodegenerative disease.

Inverted repeat structure of the Sry locus in mice

The testis-determining gene Sry is located on the short arm of the mouse Y chromosome in a region known to have undergone duplications and rearrangements in comparison with the equivalent portion of the human Y chromosome. Detailed analysis of the Sry genomic locus reveals a further difference in that the mouse Sry open reading frame lies within 2.8 kilobases of unique sequence at the center of a large inverted repeat. This repeat, which is found in both Mus musculus musculus and Mus musculus domesticus Y chromosomes, is not present at the human SRY locus. Recombination involving the repeat region may have led to an 11-kilobase deletion, precisely excising Sry in a line of XY female mice.

Mouse platelet-derived growth factor alpha receptor: sequence, tissue-specific expression and correlation with metastatic phenotype

High- and low-metastatic cells derived from metastatic murine tumors were screened for the differential expression of proto-oncogenes which may code for cell-surface receptors to growth factors. We found that metastatic clones of 3LL carcinoma and T10 sarcoma but not non-metastatic clones of these tumors express a 6.5-kb mRNA that is recognized by a v-fms probe containing a tyrosine kinase domain. The cloning and sequence analysis of a full-length cDNA clone corresponding to the v-fms-related 6.5-kb transcript showed that this transcript is the murine homolog of platelet-derived growth factor alpha (PDGF-alpha) receptor. The cDNA contains an open reading frame that predicts a 1089 amino acid protein. Comparison with the human and rat PDGF-alpha receptor reveals an overall amino acid sequence identity of 91% and 94% respectively. Northern blot analysis shows that this gene is preferentially expressed in the high-metastatic clones and is also selectively expressed in normal mouse tissues. Immunoprecipitation using anti-PDGF-alpha receptor serum shows that 185-kDa and 170-kDa proteins were specifically precipitated from cells of the high-metastatic D122 but not from the low-metastatic A9 cells. The possibility that overexpression of PDGF-alpha receptor in high-metastatic clones may contribute to an increase in the capacity of tumor cells to generate metastases in the lung is discussed.

Male development of chromosomally female mice transgenic for Sry

The initiation of male development in mammals requires one or more genes on the Y chromosome. A recently isolated gene, termed SRY in humans and Sry in mouse, has many of the genetic and biological properties expected of a Y-located testis-determining gene. It is now shown that Sry on a 14-kilobase genomic DNA fragment is sufficient to induce testis differentiation and subsequent male development when introduced into chromosomally female mouse embryos.

A gene mapping to the sex-determining region of the mouse Y chromosome is a member of a novel family of embryonically expressed genes

A gene mapping to the sex-determining region of the mouse Y chromosome is deleted in a line of XY female mice mutant for Tdy, and is expressed at a stage during male gonadal development consistent with its having a role in testis determination. This gene is a member of a new family of at least five mouse genes, related by an amino-acid motif showing homology to other known or putative DNA-binding domains.

Normal structure and expression of Zfy genes in XY female mice mutant in Tdy

Zfy-1 and Zfy-2 are candidate genes for Tdy, the testis-determining gene in mice. We have analysed these genes in a line of XY female mice that have been shown to be mutated in Tdy. We have used Southern blot analysis to show that the Zfy genes have not undergone any major structural alterations, and have also demonstrated that both genes are transcribed normally from the mutant Y chromosome (Y) in both adult XYY testis and XY female embryonic gonads. The fact that these genes show a normal structure and expression pattern in mice with a Y chromosome known to carry a mutation in Tdy and that mutant embryos develop into females despite Zfy-1 expression, strongly supports other recent evidence that Zfy genes are not directly involved in primary testis determination.

Zfy gene expression patterns are not compatible with a primary role in mouse sex determination

The Y chromosome determines maleness in mammals. A Y chromosome-linked gene diverts the indifferent embryonic gonad from the default ovarian pathway in favour of testis differentiation, initiating male development. Study of this basic developmental switch requires the isolation of the testis-determining gene, termed TDF in humans and Tdy in mice. ZFY, a candidate gene for TDF, potentially encodes a zinc-finger protein, and has two Y-linked homologues, Zfy-1 and Zfy-2, in mice. Although ZFY, Zfy-1 and Zfy-2 seem to map to the sex-determining regions of the human and mouse Y chromosomes, there is no direct evidence that these genes are involved in testis determination. We report here that Zfy-1 but not Zfy-2 is expressed in differentiating embryonic mouse testes. Neither gene, however, is expressed in We/We mutant embryonic testes which lack germ cells. These observations exclude both Zfy-1 and Zfy-2 as candidates for the mouse testis-determining gene.