TH cells primed during influenza virus infection provide help for qualitatively distinct antibody responses to subsequent immunization

The quality of the primary Ab-forming cell (AFC) response in cervical lymph nodes and mediastinal lymph nodes of mice to intranasal influenza virus was strongly influenced by viral replicative capacity. IgA secretors were prominent in the early AFC response to infectious virus in mediastinal lymph nodes, while IgG expression was more frequent among isotypically switched AFC in cervical lymph nodes of the same mice; this pattern was reversed in the response to inactivated virus. Influenza viruses A/Puerto Rico/8/34 (A/PR8) and A/X-31 share six of eight genome segments, differing only in hemagglutinin (H1 in A/PR8, H3 in A/X-31) and neuraminidase (N1 in A/PR8, N2 in A/X-31) genes. These viruses therefore elicit extensively cross-reactive TH populations, though their glycoproteins are serologically unrelated. Mice recovered from an A/X-31 infection thus mount a primary B cell response against A/PR8 glycoproteins, when challenged with the latter virus, though this response can call upon memory TH cells. To assess the impact of memory TH populations on a primary Ab response, we compared the AFC response to inactivated A/PR8 in naive mice and mice that had cleared an A/X-31 infection. A/X-31 immune mice mounted a more vigorous AFC response against A/PR8 H1 and N1 glycoproteins than naive animals, when immunized intranasally with inactivated A/PR8. However the distribution of isotypes among H1/N1-specific AFC in lymph nodes of A/X-31-primed mice resembled that of naive mice. Evidently, in this functional context, memory TH cells retained the ability to help Ab responses different in quality from that generated during their primary reaction.

Evidence on patient-doctor communication

This chapter covers important and well-studied aspects of patient-doctor communication. First the paper describes the lessons learned from studies about patients' satisfactions or dissatisfactions related to patient-doctor communication, making the point that complaints about doctors are usually due to communication problems and not technical competency issues. The next section of the chapter deals with time. It is often assumed that effective communication is inefficient. While this is not necessarily the case, the research results are complex and very interesting. The third part of the chapter covers communication in relation to patient adherence with the management plan recommended by the doctor. There is strong evidence that communication affects patient adherence and that there are four key aspects of communication that can enhance the patients' co-operation with the management plan. The final topic is patients' health. Twenty-two studies indicate the generally positive effect of key dimensions of communication on actual patient health outcomes such as pain, recovery from symptom, anxiety, functional status, and physiologic measures of blood pressure and blood glucose.

Factors influencing palliative care. Qualitative study of family physicians' practices

OBJECTIVE

To examine factors that influence family physicians' decisions to practise palliative care.

DESIGN

Qualitative method of in-depth interviews.

SETTING

Southwestern Ontario.

PARTICIPANTS

Family physicians who practise palliative care on a full-time basis, who practise on a part-time basis, or who have retired from active involvement in palliative care.

METHOD

Eleven in-depth interviews were conducted to explore factors that influence family physicians' decisions to practise palliative care and factors that sustain their interest in palliative care. All interviews were audiotaped and transcribed verbatim. The analysis strategy used a phenomenological approach and occurred concurrently rather than sequentially. All interview transcriptions were read independently by the researchers, who then compared and combined their analyses. Final analysis involved examining all interviews collectively, thus permitting relationships between and among central themes to emerge.

MAIN OUTCOME FINDINGS

The overriding theme was a common philosophy of palliative care focusing on acceptance of death, whole person care, compassion, communication, and teamwork. Participants' philosophies were shaped by their education and by professional and personal experiences. In addition, participants articulated personal and systemic factors currently affecting their practice of palliative care.

CONCLUSIONS

Participants observed that primary care physicians should be responsible for their patients' palliative care within the context of interdisciplinary teams. For medical students to be knowledgeable and sensitive to the needs of dying patients, palliative care should be given higher priority in the curriculum. Finally, participants argued compellingly for transferring the philosophy of palliative care to the overall practice of medicine.

Human parainfluenza virus type 1 immunization of infant mice protects from subsequent Sendai virus infection

Human parainfluenza virus type 1 (hPIV-1) infections are a common cause of "croup" and hospitalizations among young children, yet no vaccine is yet available. Sendai virus (mouse PIV-1) is the closest known homologue of hPIV-1. Here we address the possibility of using a xenotropic, nonpathogenic PIV as a vaccine in infants, by assessing the efficacy of hPIV-1 vaccination of infant mice against a subsequent challenge with Sendai virus. hPIV-1 was administered intranasally to mice age 3-6 days and shown by serum antibody ELISA and elispot analysis to elicit virus-specific IgM and isotype-switched antibody-forming cells (AFC). The response was completely cross-reactive between hPIV-1 and Sendai virus. Mice were challenged with Sendai virus 6-8 weeks later and generated AFC and serum antibody responses composed of IgM, as well as IgG and IgA, unlike challenged, age-matched controls. The high IgM response among AFC was not seen in mice primed as adults with hPIV-1 and challenged with Sendai virus. The hPIV-1 priming of infant mice afforded protection, as the majority of these mice survived the lethal Sendai virus challenge, as did all adult primed animals. These data support the notion that the unmodified xenotropic Sendai virus might function effectively in human infants as a vaccine against hPIV-1.

Differential antigen burden modulates the gamma interferon but not the immunoglobulin response in mice that vary in susceptibility to Sendai virus pneumonia

Sendai virus, a paramyxovirus which causes murine pneumonia, grew to approximately 10-fold higher titers and was cleared less rapidly from the lungs of 129/J (129) than H-2b-compatible C57BL/6J (B6) mice. The more susceptible 129 mice also made higher titers of gamma interferon (IFN-gamma) and immunoglobulin G2a (IgG2a) virus-specific antibody. Analysis with acutely irradiated (950 rads) mice and immunologically reconstituted bone marrow (BM) radiation chimeras indicated that the enhanced virus growth was a function of the radiation-resistant respiratory epithelium. Prolonged exposure to more virus in turn influenced the magnitude of IFN-gamma production, most of which was made by CD4+ T lymphocytes. Somewhat surprisingly, however, the 129 pattern of a higher virus-specific serum Ig response skewed towards IgG2a mapped to the reconstituting BM. Thus, the characteristics of the humoral response are at least partly dissociated from both the antigen load, resulting from viral replication, and the level of IFN-gamma production. Further analysis of double chimeras (B6+129 BM-->B6 recipients) confirmed that the divergent humoral immune response to Sendai virus in B6 and 129 mice is largely determined by the inherent characteristics of the lymphoid cells.

Distinctive kinetics of the antibody-forming cell response to Sendai virus infection of mice in different anatomical compartments

The single-cell ELISPOT assay was used to determine the frequency and isotype commitment of virus-specific antibody-forming cells (AFC) at different anatomical locations following intranasal Sendai virus infection of C57BL/6 and 129/Sv mice. AFC responses in the mediastinal and cervical lymph nodes showed sharp increases and declines, first of IgM AFC, peaking about 7 days after infection, and then of IgG and IgA AFC, peaking about 10 days after infection. A wave of IgM AFC preceding the other isotypes was less evident in the spleen, where peak frequencies of AFC occurred 14 days after infection. Virus-specific AFC appeared in the bone marrow with a unique kinetic pattern, increasing in frequency gradually over the first 3 weeks after infection to a plateau that remained constant. Circulating IgM and IgG achieved significant titers approximately a week after infection; IgM titers were transient, but IgG levels increased sharply and remained high, reflecting the longevity of the bone marrow AFC response. Strain differences in isotype bias were noted, particularly preferential switching to the gamma 2a gene in 129/Sv mice. The B-cell response to acute respiratory viral infection thus exhibits features that are distinct from the primary response to nonreplicating antigens.

Respiratory virus infection of mice provokes a permanent humoral immune response

We have observed that respiratory virus infection of mice provokes an extremely persistent humoral immune reaction, due to a long-sustained population of antibody-secreting cells in the bone marrow. Theories of humoral immunity that strongly distinguish primary and secondary reactions thus may not adequately describe the immune response to respiratory viruses.

Administration of anti-IFN-gamma antibody to beta 2-microglobulin-deficient mice delays influenza virus clearance but does not switch the response to a T helper cell 2 phenotype

Treatment of mice that were homozygous for a beta 2-microglobulin gene disruption with a mAb that was specific for IFN-gamma delayed clearance of an influenza A virus from the respiratory tract for at least 3 days, whereas administration of an anti-IL-4 mAb had no effect. However, all mice survived and eventually cleared the virus. The anti-IFN-gamma significantly decreased both the level of class II MHC glycoprotein expression and the numbers of CD4+ lymphocytes in the inflammatory populations recovered by bronchoalveolar lavage of the pneumonic lung, whereas the total cell counts remained the same. These differences were not apparent for the regional mediastinal lymph nodes, although the frequency of lymph node B cells producing virus-specific Ab of the IgG2a subclass was greatly reduced. However, neither the anti-IFN-gamma nor anti-IL-4 treatments drastically altered the cytokine production profiles detected for freshly isolated lymphocytes by the using single cell ELISPOT assay or by ELISA of culture supernatants after in vitro restimulation with virus. Thus, neutralization of secreted IFN-gamma during the course of an influenza-specific response in beta 2-microglobulin-deficient mice that lack CD8+ T cells delays virus clearance and modifies the character of the host response, but does not cause the CD4+ subset to switch to a Th2 cytokine profile.

Administration of anti-IFN-gamma antibody to beta 2-microglobulin-deficient mice delays influenza virus clearance but does not switch the response to a T helper cell 2 phenotype

Treatment of mice that were homozygous for a beta 2-microglobulin gene disruption with a mAb that was specific for IFN-gamma delayed clearance of an influenza A virus from the respiratory tract for at least 3 days, whereas administration of an anti-IL-4 mAb had no effect. However, all mice survived and eventually cleared the virus. The anti-IFN-gamma significantly decreased both the level of class II MHC glycoprotein expression and the numbers of CD4+ lymphocytes in the inflammatory populations recovered by bronchoalveolar lavage of the pneumonic lung, whereas the total cell counts remained the same. These differences were not apparent for the regional mediastinal lymph nodes, although the frequency of lymph node B cells producing virus-specific Ab of the IgG2a subclass was greatly reduced. However, neither the anti-IFN-gamma nor anti-IL-4 treatments drastically altered the cytokine production profiles detected for freshly isolated lymphocytes by the using single cell ELISPOT assay or by ELISA of culture supernatants after in vitro restimulation with virus. Thus, neutralization of secreted IFN-gamma during the course of an influenza-specific response in beta 2-microglobulin-deficient mice that lack CD8+ T cells delays virus clearance and modifies the character of the host response, but does not cause the CD4+ subset to switch to a Th2 cytokine profile.

Phenotypic inhibition of the renin-angiotensin system, emergence of the Ren-2 gene, and adaptive radiation of mice

The renin-angiotensin system in sub-genus Mus displays unique features including duplication of the renin gene in most strains, strong expression of the second gene in submandibular gland of males, and inhibited responses to injected renin. Our findings indicate that this inhibition results from a paucity of renin substrate and is consistent with first-order kinetics. We find substrate paucity to be a feature of both sexes and all sub-species and strains of Mus irrespective of gene duplication. Attempts to increase the level of substrate in blood by intravenous injection caused marked increases in blood pressure in Mus, suggesting that substrate paucity was a phenotypic prerequisite for successful emergence of enhanced renin expression in salivary gland. We propose that these phenomena are linked to salivary "lethal factor", possibly transferred by biting, in an evolutionary sequence that has provided a major selective advantage for Mus and influenced the ecology and evolution of rodents.