Neighborhood effects on the health of elderly persons: evidence from China

BACKGROUND

Presently, global aging has become increasingly serious, whereas the health concerns brought by aging have become a public issue that warrants an urgent solution from all countries across the world. Therefore, this research paper discusses the influence of neighborhood health on elderly individuals' health, and extending a realistic basis for the other economies to improve the neighborhood environment and promote the health of the elderly.

METHODS

Based on the data of CHARLS2018, this research paper adopts the samples that fulfill the study requirements (N = 7326). we constructed a comprehensive research framework integrating oprobit regression model, heterogeneity analysis, conditional mixed process(CMP)robustness testing, Furthermore, the KHB decomposition method is implemented to ascertain the influential mechanism of NMH and NPH on the mental- and physical health of elderly persons.

RESULTS

The oprobit regression model analysis indicates that NMH 0.434 and NPH 0.550 exert positive influences on the elderly's mental- and physical health. Meanwhile, the effects of conditional mixed process on NMH and NPH stand at 0.381 and4.372, which are different from the oprobit regression results; thereby, indicating the existence of endogeneity. Afterward, KHB mediating effect confirms that Internet use, gift reciprocity, and charity activity contribute 30.21% and 16.83% to mental- and physical health, respectively.

CONCLUSIONS

Firstly, the NMH and NPH demonstrate a positive influence on the mental- and physical health of the elder population. However, there exist heterogeneous differences. Secondly, the conditional mixed process deals with the endogeneity of NMH and NPH. Thirdly, social integration, social interaction, and social engagement serve as significant transmission mechanisms for the influences of NMH and NPH on the health of elderly persons.

Dysregulation of CD30+ T cells by leukemia impairs isotype switching in normal B cells

Chronic lymphocytic leukemia (CLL) is associated with impaired immunoglobulin (Ig) class-switching from IgM to IgG and IgA, a defect that leads to recurrent infections. When activated in the presence of leukemic CLL B cells, T cells rapidly up-regulate CD30 through an OX40 ligand and interleukin 4 (IL-4)-dependent mechanism. These leukemia-induced CD30+ T cells inhibit CD40 ligand (CD40L)-mediated S mu-->S gamma and S mu-->S alpha class-switch DNA recombination (CSR) by engaging CD30 ligand (CD30L), a molecule that interferes with the assembly of the CD40-tumor necrosis factor receptor-associated factor (TRAF) complex in nonmalignant IgD+ B cells. In addition, engagement of T cell CD30 by CD30L on neoplastic CLL B cells down-regulates the CD3-induced expression of CD40L. These findings indicate that, in CLL, abnormal CD30-CD30L interaction impairs IgG and IgA production by interfering with the CD40-mediated differentiation of nonmalignant B cells.

Ongoing hypermutation in the Ig V(D)J gene segments and c-myc proto-oncogene of an AIDS lymphoma segregates with neoplastic B cells at different sites: implications for clonal evolution

To investigate the role of somatic Ig hypermutation in the evolution of AIDS-associated B cell lymphomas, we analyzed the Ig V(D)J and c-myc genes expressed by neoplastic B cells in two extranodal sites, testis and orbit, and clonally related cells in the bone marrow. Testis and orbit B cells expressed differentially mutated but collinear V(H)DJ(H), V kappa J kappa and c-myc gene sequences. Shared mutations accounted for 10.2%, 8.4%, and 4.3% of the overall V(H)DJ(H), V kappa J kappa, and c-myc gene sequences. Tumor-site specific V(H)DJ(H), V kappa J kappa, and c-myc mutations were comparable in frequency, and a single point-mutation gave rise to an EcoRI site in the testis c-myc DNA. Both shared and tumor site-specific V(H)DJ(H), V kappa J kappa, and c-myc mutations displayed predominance of transitions over transversions. The "neoplastic" V(H)DJ(H) sequence was expressed by about 10(-5) cells in the bone marrow, and contained two of the three orbital, but none of the testicular V(H)DJ(H) mutations. The nature and distribution of the Ig V(D)J mutations found in the kappa chain suggested a selection by antigen in testis and orbit. Our data suggest that, in AIDS-associated B cell lymphomas, the Ig hypermutation machinery targets V(H)DJ(H), V kappa J kappa, and c-myc genes with comparable efficiency and modalities.

B cell receptor engagement and T cell contact induce Bcl-6 somatic hypermutation in human B cells: identity with Ig hypermutation

The human bcl-6 proto-oncogene has been found to be mutated in both neoplastic and normal B cells. We used CL-01 cells, our monoclonal model of germinal center differentiation, and normal human B cells to explore the induction requirements and the modalities of bcl-6 hypermutation. As we have previously shown, CL-01 cells are IgM+ IgD+ and effectively mutate the expressed Ig VHDJH and V lambda J lambda genes and switch to IgG, IgA, and IgE upon B cell receptor engagement and contact with CD4+ T cells through CD40:CD154 and CD80:CD28 coengagement. In this paper we showed that the same stimuli induce somatic hypermutation of bcl-6 in CL-01 and normal IgM+ IgD+ B cells. bcl-6 hypermutation was not accompanied by translocation of this proto-oncogene or hypermutation of the beta-actin gene, and it did mimic Ig hypermutation. It was associated with transcription initiation, in that it targeted the first exon and a 696-bp sequence immediately downstream (approximately 0.6 kb) of the transcription initiation site while sparing further downstream (approximately 2.5 kb) and upstream (approximately 0.1 kb) areas. bcl-6 hypermutation displayed an overall rate of 2.2 x 10-4 changes/base/cell division with characteristic nucleotide preferences and showed strand polarity. These findings show that B cell receptor engagement promotes hypermutation in genes other than Ig, and suggest that cis-regulating elements similar to those of the Ig locus exist in bcl-6.

Engagement of CD153 (CD30 ligand) by CD30+ T cells inhibits class switch DNA recombination and antibody production in human IgD+ IgM+ B cells

CD153 (CD30 ligand) is a member of the TNF ligand/cytokine family expressed on the surface of human B cells. Upon exposure to IL-4, a critical Ig class switch-inducing cytokine, Ag-activated T cells express CD30, the CD153 receptor. The observation that dysregulated IgG, IgA, and/or IgE production is often associated with up-regulation of T cell CD30 prompted us to test the hypothesis that engagement of B cell CD153 by T cell CD30 modulates Ig class switching. In this study, we show that IgD+ IgM+ B cells up-regulate CD153 in the presence of CD154 (CD40 ligand), IL-4, and B cell Ag receptor engagement. In these cells, CD153 engagement by an agonistic anti-CD153 mAb or T cell CD30 inhibits S mu-->Sgamma, Smu-->Salpha, and S mu-->Sepsilon class switch DNA recombination (CSR). This inhibition is associated with decreased TNFR-associated factor-2 binding to CD40, decreased NF-kappaB binding to the CD40-responsive element of the Cgamma3 promoter, decreased Igamma3-Cgamma3 germline gene transcription, and decreased expression of Ku70, Ku80, DNA protein kinase, switch-associated protein-70, and Msh2 CSR-associated transcripts. In addition, CD153 engagement inhibits IgG, IgA, and IgE production, and this effect is associated with reduced levels of B lymphocyte maturation protein-1 transcripts, and increased binding of B cell-specific activation protein to the Ig 3' enhancer. These findings suggest that CD30+ T cells modulate CSR as well as IgG, IgA, and IgE production by inducing reverse signaling through B cell CD153.

The evolutionarily conserved sequence upstream of the human Ig heavy chain S gamma 3 region is an inducible promoter: synergistic activation by CD40 ligand and IL-4 via cooperative NF-kappa B and STAT-6 binding sites

Germline C gamma gene transcription is a crucial event in the process that leads to switch DNA recombination to IgG, but its regulation in the human is poorly understood. We took advantage of our monoclonal model of germinal center B cell differentiation, IgM+ IgD+ CL-01 cells, to define the role of the I gamma 3 evolutionarily conserved sequence (ECS) in the germline transcriptional activation of the human C gamma 3 gene. The I gamma 3 ECS lies upstream of the major I gamma 3 transcription initiation site and displays more than 90% identity with the corresponding human I gamma 1, I gamma 2, and I gamma 4 regions. Reporter luciferase gene vectors containing the human gamma 3 ECS were used to transfect CL-01 cells, which have been shown to undergo Smu-->S gamma 3 DNA recombination, upon engagement of CD40 by CD40 ligand (CD40L) and exposure to IL-4. In these transfected CL-01 cells, CD40:CD40L engagement and exposure to IL-4 synergistically induced gamma 3 ECS-dependent luciferase reporter gene activation. Targeted mutational analysis demonstrated that a tandem NF-kappa B/Rel binding motif is critical for the gamma 3 ECS responsiveness to both CD40L and IL-4, while a STAT-6-binding site is additionally required for IL-4 inducibility. Electrophoretic mobility shift assays showed that p50/p65/c-Rel and STAT-6 are effectively induced by CD40L and IL-4, respectively, and bind to specific DNA motifs within the ECS. These partially overlapping CD40L and IL-4 responsive elements are functionally cooperative as the disruption of one of them prevents synergistic promoter activation. Thus, the gamma 3 ECS is an inducible promoter containing cis elements that critically mediate CD40L and IL-4-triggered transcriptional activation of the human C gamma 3 gene.

CD40 engagement triggers switching to IgA1 and IgA2 in human B cells through induction of endogenous TGF-beta: evidence for TGF-beta but not IL-10-dependent direct S mu-->S alpha and sequential S mu-->S gamma, S gamma-->S alpha DNA recombination

IgA are major effectors of antimicrobial defense in the respiratory and digestive tracts. We have analyzed the requirements for and the modalities of switching to IgA using our recently identified monoclonal model of human germinal center differentiation, CL-01 B cells. CL-01 cells bear surface IgM (sIgM) and sIgD and switch to all seven downstream isotypes in response to physiologic stimuli. In these cells, CD40 engagement by CD40 ligand induces production of endogenous TGF-beta and IL-10, expression of germline Ialpha1-Calpha1 and Ialpha2-Calpha2 transcripts, mature VHDJH-Calpha1 and VHDJH-Calpha2 transcripts, and IgA secretion. These events are associated with not only direct Smu-->Salpha, but also sequential Smu-->Sgamma, Sgamma-->Salpha DNA recombination, and are ablated by neutralizing anti-TGF-beta but not IL-10 Ab, and indicating that TGF-beta, not IL-10, is a crucial mediator of the transcriptional activation and recombination of human Calpha1 and Calpha2 genes. Our findings in CL-01 cells were reproduced in freshly isolated naive sIgM+ sIgD+ B lymphocytes. Thus, engagement of CD40, in the absence of other (known) stimuli, is sufficient to effectively induce switching to IgA in human B cells. This is effected by direct and sequential DNA recombination events, which are both dependent upon endogenous TGF-beta secreted by the CD40L-induced B cells.

Temperature-induced expression of human-mouse chimeric Fab

The temperature-induced expression vector pHZ01 with lambda PRPL promoter for the efficient expression of human-mouse chimeric Fab was constructed. Three kinds of chimeric Fab were expressed in E. coli: anti-prostate specific antigen (PSA) chimeric Fab, anti-lysozyme (HEL) chimeric Fab, and anti-tetanus toxoid (TT) chimeric Fab. All the soluble chimeric Fabs expressed showed specific antigen-binding activities.

[Cloning of variable region genes of anti-tetanus toxoid antibody and their expression as three kinds of engineered antibodies in E. coli]

The heavy and light chain variable region genes of anti-tetanus toxoid (TT) antibody and the heavy chain Fd genes were amplified and cloned through RT-PCR from mouse hybridoma cells. The sequences of VH and VK were determined. Fd gene fragments were expressed in E. coli. The ELISA results indicated that the expressed Fd showed antigen binding activity but was nonspecific. Furthermore, through SOE and PCR techniques, the VH and VK gene fragments together with ScFv linker were assembled into single chain antibody (ScFv) gene fragment. While together with human heavy chain CH 1 gene fragment and Fab linker, they were assembled into chimeric Fab gene fragment. The two assembled gene fragments were separately inserted into phagemid pHEN 1, which was a fd-based vector containing gene 3 encoding the minor coat protein. In presence of helper phage M 13-VCS the anti-TT phage-ScFv or phage-Fab were displayed on the surface of phage particles respectively. Results from phage-ELISA indicated that both phage antibodies were TT-specific.