An online survey to understand the needs of caregivers of family members with 22q11 deletion syndrome.

BACKGROUND: Most individuals with 22q11.2 deletion syndrome (22q11DS) have multi-system and lifelong needs requiring substantial support. Their primary caregivers are usually family members who dedicate lifelong time and effort to their role. The pressures of their roles can negatively impact caregivers' psychosocial well-being, suggesting a need for additional support for this community who currently have no specialised interventions available. METHOD: This online study surveyed 103 caregivers of family members with 22q11DS to determine the barriers to accessing support that they faced, the kind of support they would value and whether an online intervention could meet their needs. RESULTS: The caregivers indicated that a brief online intervention focused on teaching practical skills and connecting them with a peer network of support would be most valuable. CONCLUSIONS: Future studies are planned that will build on these results by designing and testing online interventions tailored to this community.

Telomere length, telomerase activity, and replicative potential in HIV infection: analysis of CD4+ and CD8+ T cells from HIV-discordant monozygotic twins.

To address the possible role of replicative senescence in human immunodeficiency virus (HIV) infection, telomere length, telomerase activity, and in vitro replicative capacity were assessed in peripheral blood T cells from HIV+ and HIV- donors. Genetic and age-specific effects on these parameters were controlled by studying HIV-discordant pairs of monozygotic twins. Telomere terminal restriction fragment (TRF) lengths from CD4+ T cells of HIV+ donors were significantly greater than those from HIV- twins. In contrast, telomere lengths in CD8+ T cells from HIV+ donors were shorter than in HIV- donors. The in vitro replicative capacity of CD4+ cells from HIV+ donors was equivalent to that of HIV- donors in response to stimulation through T cell receptor CD3 and CD28. Little or no telomerase activity was detected in freshly isolated CD4+ or CD8+ lymphocytes from HIV+ or HIV- donors, but was induced by in vitro stimulation of both HIV+ and HIV- donor cells. These results suggest that HIV infection is associated with alterations in the population dynamics of both CD4+ and CD8+ T cells, but fail to provide evidence for clonal exhaustion or replicative senescence as a mechanism underlying the decline in CD4+ T cells of HIV-infected donors.

Tales of tails: regulation of telomere length and telomerase activity during lymphocyte development, differentiation, activation, and aging.

Telomerase activity and the regulation of telomere length are factors which have been implicated in the control of cellular replication. These variables have been examined during human lymphocyte development, differentiation, activation, and aging. It was found that telomere length of peripheral blood CD4+ T cells decreases with age as well as with differentiation from naive to memory cells in vivo, and decreases with cell division in vitro. These results provide evidence that telomere length correlates with lymphocyte replicative history and residual replicative potential. In contrast, telomere length appears to increase during tonsil B-cell differentiation and germinal center (GC) formation in vivo. It was also found that telomerase activity is highly regulated during T-cell development and B-cell differentiation in vivo, with high levels of telomerase activity expressed in thymocytes and GC B cells, and low levels of telomerase activity in resting mature peripheral blood lymphocytes. Finally, resting lymphocytes retain the ability to upregulate telomerase activity upon activation, and this capacity does not appear to decline with age. Although the precise role of telomerase in lymphocyte function remains to be elucidated, telomerase may contribute to protection from telomere shortening in T and B lymphocytes, and may thus play a critical role in lymphocyte development, differentiation and activation. The future study of telomerase and its regulation of telomere length may enhance our understanding of how the replicative lifespan is regulated in lymphocytes.

The role of CD28 costimulation in immune-mediated responses against mouse mammary tumor viruses.

Infectious mouse mammary tumor viruses (MMTV) encode superantigens (SAg) which, when presented in association with permissive class II MHC molecules, are recognized by those T cells that express appropriate TCRs. Recent findings have indicated that expression of a permissive MHC class II product and of a specific TCR are also critical to susceptibility of newborn mice to infection with milk-borne MMTV, suggesting that SAg-mediated T cell activation may play a facilitating role in viral infection. Because effective Ag-specific T cell activation can require costimulatory signals in addition to TCR-mediated recognition, the role of the CD28 costimulatory receptor was analyzed in responses of neonatal and adult mice to MMTV challenge. Mice that were deficient in CD28 expression as a result of gene targeting were compared with CD28-intact littermates. In response to parenteral challenge with MMTV, CD28-deficient adult mice exhibited reduced expansion of MMTV SAg-reactive T cells in draining LNs, decreased cytokine production, and decreased B cell activation and Ig secretion. These results indicate that optimal T and B cell responses to MMTV challenge, as reflected in the parameters measured, are CD28 dependent. In contrast, CD28 absence did not impair TCR-V beta-specific clonal deletion induced by neonatal exposure to MMTV. Further, analysis of susceptibility to viral infection in neonatally exposed mice revealed that CD28 deficiency did not interfere with SAg-dependent MMTV infection. Failure to identify CD28 dependence of MMTV infection suggests either the absence of a costimulatory requirement in the events that lead to viral infection or a redundancy in costimulatory signals that support infection.

Superantigenic characteristics of mouse mammary tumor viruses play a critical role in susceptibility to infection in mice.

Mouse mammary tumor viruses (MMTV) are retroviruses that induce mammary carcinomas. An interesting feature of these viruses is the superantigen (SAg) encoded in an open reading frame within the 3' long terminal repeat. The mechanism by which ingestion of milk-borne virus results in infection of the host mammary tissue remains incompletely understood. However, a working model has been proposed in which the interaction between viral SAg, T-cell receptor and MHC class II I-E facilitates viral replication and hence infectivity. In this review we summarize current studies demonstrating the role of SAg stimulation in susceptibility to MMTV infection.

Mechanisms of adoptive immunotherapy: improved methods for in vivo tracking of tumor-infiltrating lymphocytes and lymphokine-activated killer cells.

Adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) and lymphokine-activated killer cells has been demonstrated to mediate regression of tumors in murine models and in selected patients with advanced cancer. Improved methods for monitoring immune cell traffic, particularly to sites of tumor, are needed to elucidate mechanisms of antitumor activity and optimize treatment protocols. Traditional cell tracking methods such as fluorescent protein labeling and radiolabeling using 111In, 125I, or 51Cr are limited by isotope half-life, leakage or transfer of label from immune cells, and toxicity or altered cell function caused by the labeling process. Labeling with genetic markers allows long-term cell tracking but is laborious to perform and difficult to quantitate. We have used two recently described lipophilic cell tracking compounds (PKH26 and 125I-PKH95) which stably partition into lipid regions of the cell membrane to track immune cells in vivo. Concentrations of each tracking compound which had no adverse effects were determined for a variety of murine TIL and lymphokine-activated killer cell functions. Viability was unimpaired at labeling concentrations of up to 5 microM for PKH95 and 20 microM for PKH26. TIL proliferation was unaltered by labeling with up to 5 microM PKH95, 20 microM PKH26, or a combination of 15 microM PKH26 and 5 microM PKH95. In vivo cytotoxic effector function and in vivo therapeutic efficacy of lymphokine-activated killer cells and TIL were also unimpaired by labeling with 20 microM PKH26 or 1 microM 125I-PKH95. Subsequent studies in an adoptive transfer immunotherapy model used 125I-PKH95 to track the biodistribution of TIL in tumor and in non-tumor-bearing animals and PKH26 fluorescence to monitor microdistribution within tissues and distinguish TIL from host T-cells. The results suggest that differential accumulation, selective retention, or proliferation at the tumor site cannot account for the observed pattern of therapeutic efficacy. We hypothesize that a minimum number of TIL must reach the tumor site in order to achieve a demonstrable therapeutic effect.

Abdominal surgical wound infection is lowered with improved perioperative enterococcus and bacteroides therapy.

Perioperative antibiotics decrease surgical wound infection (SWI) in trauma patients requiring abdominal exploration. This investigation evaluated 24 hours of cefoxitin or ampicillin/sulbactam used for early therapy in such patients. Patients were randomly assigned to one of two treatment groups. The primary endpoint evaluated was SWI, which was defined as purulent drainage or active wound treatment. Five hundred ninety-two patients were evaluated: 283 received ampicillin/sulbactam and 309 received cefoxitin. The incidence of wound infection among the ampicillin/sulbactam patients was 2% and among cefoxitin patients it was 7% (p < 0.004). The cefoxitin patients with colon injuries were analyzed (p < 0.007). The major difference between the two groups was an increased incidence of enterococcal infections in the cefoxitin-treated patients. A single broad-spectrum antibiotic given for 24 hour perioperatively effectively controls SWI. Use of ampicillin/sulbactam results in a significantly lower SWI rate than use of cefoxitin, which may be a result of improved enterococcal and Bacteroides coverage.

Association of a V beta 2-specific superantigen with a tumorigenic milk-borne mouse mammary tumor virus.

A number of endogenous mouse mammary tumor virus (MMTV) proviruses encode superantigens that have the property of stimulating mature T lymphocytes in a TCR V beta-specific fashion and of mediating V beta-specific clonal deletion in developing T cells. The tumorigenic milk-borne MMTV carried by C3H and GR mice also have superantigen properties in vivo, and it has been proposed that this superantigenic function is critical to the infectivity and/or tumorigenicity of the virus. To test the requirement for superantigen properties in tumorigenic MMTV, a highly tumorigenic strain of MMTV isolated from BALB/c mice (BALB/cV virus) was analyzed for its effect on TCR V beta expression. It was found that exposure of newborn mice to milk-borne virus results in marked deletion of V beta 2-expressing CD4+ peripheral T cells. This deletion is detected in mature TCRhigh thymocytes as well as in peripheral T cells from virus-exposed mice. Deletion is dependent on expression of a permissive MHC type in mice exposed to virus. Subcutaneous injection of adult mice with virus-containing milk induces a substantial increase in V beta 2+ CD4+ cells in draining lymph nodes within 4 days. Thus, tumorigenic BALB/cV is associated with V beta 2-specific superantigen activity capable of mediating both T cell expansion and clonal deletion in vivo. These findings are consistent with a critical role of superantigen-mediated T cell activation in MMTV infection and tumorigenesis.

Bovine natural killer-like cell responses against cell lines expressing recombinant bovine herpesvirus type 1 glycoproteins.

The murine retrovirus shuttle vector pZipNeo SV(X)1 was used to construct plasmids encoding the three major surface glycoproteins of bovine herpesvirus-1 (BHV-1). Each plasmid was transfected into D17, a canine osteosarcoma cell line sensitive to lysis by bovine NK-like cells when infected with BHV-1. After selection in G418 sulfate, cell lines expressing the recombinant gene products were sorted by flow microfluorimetry, radioimmunoprecipitated, and analyzed by SDS-PAGE for fidelity as compared to the native viral glycoproteins. Two of the three genetically engineered cell lines (gI and gIV) could successfully serve as targets to detect bovine NK-like cytolysis. These findings support and extend a previous study from our laboratory indicating a role for BHV-1 glycoproteins in the cytolytic response by bovine NK-like cells. Additionally, this study demonstrated that individual proteins are recognized by these effector cells, and that recombinant glycoproteins can direct cytolytic activity in the absence of host cell infection-associated proteins. This is the first known report of Ag directed cytotoxicity by bovine null (non-B, non-T) cells.