Evaluating the nutritional content of an insect-fortified food for the child complementary diet in Ghana

BACKGROUND

Due to rising food insecurity, natural resource scarcity, population growth, and the cost of and demand for animal proteins, insects as food have emerged as a relevant topic. This study examines the nutrient content of the palm weevil larva (Rhynchophorus phoenicis), a traditionally consumed edible insect called akokono in Ghana, and assesses its potential as an animal-source, complementary food.

METHODS

Akokono in two "unmixed" forms (raw, roasted) and one "mixed" form (akokono-groundnut paste) were evaluated for their macronutrient, micronutrient, amino acid, and fatty acid profiles.

RESULTS

Nutrient analyses revealed that a 32 g (2 tbsp.) serving of akokono-groundnut paste, compared to recommended daily allowances or adequate intakes (infant 7-12 months; child 1-3 years), is a rich source of protein (99%; 84%), minerals [copper (102%; 66%), magnesium (54%; 51%), zinc (37%; 37%)], B-vitamins [niacin (63%; 42%), riboflavin (26%; 20%), folate (40%; 21%)], Vitamin E (a-tocopherol) (440%; 366%), and linoleic acid (165%; 108%). Feed experiments indicated that substituting palm pith, the typical larval diet, for pito mash, a local beer production by-product, increased the carbohydrate, potassium, calcium, sodium, and zinc content of raw akokono. Akokono-groundnut paste meets (within 10%) or exceeds the levels of essential amino acids specified by the Institute of Medicine criteria for animal-source foods, except for lysine.

CONCLUSIONS

Pairing akokono with other local foods (e.g., potatoes, soybeans) can enhance its lysine content and create a more complete dietary amino acid profile. The promotion of akokono as a complementary food could play an important role in nutrition interventions targeting children in Ghana.

Adolescent access to and utilisation of health services in two regions of Côte d'Ivoire: A qualitative study

Adolescence is a critical time for physical, cognitive, social and emotional development, yet adolescents are prone to unique barriers and unmet needs for receiving proper health care services and information. This study explored barriers and facilitators to adolescent (15-19 years) access to and utilisation of health services in two regions of Côte d'Ivoire. Focus group discussions were conducted with adolescent females and males, caregivers, and health care workers at eight health facilities. Barriers and facilitators emerged within three themes: cultural, structural, and 'accueil', a French term encompassing overall feelings and experiences of a situation. Cultural barriers included community beliefs and stigma, and adolescent knowledge, while caregiver support and medical preference were both barriers and facilitators. Structural barriers included financial costs, distance to health facilities, waiting times, and lack of supplies and medications. Feelings of fear, shame and discomfort were barriers related to 'accueil' while interactions with health care workers were both barriers and facilitators. Similarities and differences in perspectives arose between groups. Future work to increase adolescent access to and utilisation of health services should take into consideration both participant recommendations and the interconnectedness of the barriers faced to create multidimensional approaches that improve health outcomes for this priority population.

Naturally Fermented Milk From Northern Senegal: Bacterial Community Composition and Probiotic Enrichment With Lactobacillus rhamnosus

A variety of foods fermented with lactic acid bacteria serve as dietary staples in many African communities; yet, their bacterial profiles are poorly characterized. The integration of health-promoting probiotics into naturally fermented milk products could make a profound impact on human health. Here, we characterize the bacterial community composition of a naturally fermented milk product (lait caillé) from northern Senegal, prepared in wooden bowls (lahals) with a bacterial biofilm to steer the fermentation process. We incorporated a probiotic starter culture containing the most documented probiotic strain Lactobacillus rhamnosus GG (generic strain name yoba 2012) into the local fermentation process. Bar-coded 16S rRNA amplicon sequencing of lait caillé samples indicated that the bacterial community of lait caillé has high species richness with over 100 bacterial genera; however, few have high abundance. In contrast to the diverse bacterial compositions of other characterized naturally fermented milk products, the composition of lait caillé predominantly consists of the lactic acid bacteria Streptococcus and Lactobacillus, resembling the bacterial composition in regular yogurt. The bacterial community composition of lait caillé varies geographically based on the presence of some genera, including Lactoccoccus, Enterococcus, Bifidobacterium, and Bacillus, but this trend is not consistent within production communities. The diversity of bacterial communities is much higher in the lahal biofilm than in the naturally fermented milk products, which is in turn greater than in commercial yogurts. Addition of a starter culture with L. rhamnosus yoba 2012 to milk in lahals led to substantial growth of this probiotic bacterium during the fermentation process. Two independent quantitative PCR-analyses specific for L. rhamnosus yoba 2012 indicated a 20- to 60-fold increase in the total number of probiotic bacteria in the first batch after inoculation. A similar increase of the probiotic was observed in a variation of lait caillé prepared with carbohydrate-rich millet granules (thiakry) added prior to fermentation. This study shows the feasibility of integrating health-promoting probiotic strains into naturally fermented foods produced in regions with a high prevalence of malnutrition.

In silico programming of degradable microparticles to hide and then reveal immunogenic payloads in vivo

Poly(lactic-co-glycolic) acid microparticles, mathematically designed for delayed release in vitro, hide and then reveal ovalbumin-alum in vivo without altering its immunogenicity.

Expanding CEP290 mutational spectrum in ciliopathies

Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert syndrome and related disorders (JSRD), Meckel syndrome (MKS), Senior-Loken syndrome and isolated Leber congenital amaurosis (LCA). Although these conditions are recessively inherited, in a subset of patients only one CEP290 mutation could be detected. To assess whether genomic rearrangements involving the CEP290 gene could represent a possible mutational mechanism in these cases, exon dosage analysis on genomic DNA was performed in two groups of CEP290 heterozygous patients, including five JSRD/MKS cases and four LCA, respectively. In one JSRD patient, we identified a large heterozygous deletion encompassing CEP290 C-terminus that resulted in marked reduction of mRNA expression. No copy number alterations were identified in the remaining probands. The present work expands the CEP290 genotypic spectrum to include multiexon deletions. Although this mechanism does not appear to be frequent, screening for genomic rearrangements should be considered in patients in whom a single CEP290 mutated allele was identified.

Variability in hemoglobin levels: clinical implications. Case study of the anemic patient

A historical, prospective, multicenter, observational study was conducted on data from October 1996 to December 1997 to determine the impact of hemoglobin (Hb) variability on the interpretation of maintenance anemia management outcomes in hemodialysis patients. Trends in mean Hb levels were retrospectively analyzed to determine whether there were any differences between 1-month Hb averages versus 3- or 6-month rolling averages. Results showed that: (a) Hb measurements exhibit wide variability between patients and within patients, regardless of the assessment method used, and (b) it is difficult to maintain patients within the 1 g/dL Hb spread recommended by NKF-K/DOQI. The largest variations in Hb readings were observed in 1-month readings, while 6-month rolling averages exhibited the least variability. These data illustrate the importance of assessing long-term trends in laboratory data before making incremental or decremental modifications in the anemia prescription.

Hematopoietic stem cell maintenance and differentiation are supported by embryonic aorta-gonad-mesonephros region-derived endothelium

Hematopoietic stem cells are capable of extensive self-renewal and expansion, particularly during embryonic growth. Although the molecular mechanisms involved with stem cell maintenance remain mysterious, it is now clear that an intraembryonic location, the aorta-gonad-mesonephros (AGM) region, is a site of residence and, potentially, amplification of the definitive hematopoietic stem cells that eventually seed the fetal liver and adult bone marrow. Because several studies suggested that morphologically defined hematopoietic stem/progenitor cells in the AGM region appeared to be attached in clusters to the ventrally located endothelium of the dorsal aorta, we derived cell lines from this intraembryonic site using an anti-CD34 antibody to select endothelial cells. Analysis of two different AGM-derived CD34(+) cell lines revealed that one, DAS 104-8, efficiently induced fetal-liver hematopoietic stem cells to differentiate down erythroid, myeloid, and B-lymphoid pathways, but it did not mediate self-renewal of these pluripotent cells. In contrast, a second cell line, DAS 104-4, was relatively inefficient at the induction of hematopoietic differentiation. Instead, this line provoked the expansion of early hematopoietic progenitor cells of the lin-CD34(+)Sca-1(+)c-Kit+ phenotype and was proficient at maintaining fetal liver-derived hematopoietic stem cells able to competitively repopulate the bone marrow of lethally irradiated mice. These data bolster the hypothesis that the endothelium of the AGM region acts to mediate the support and differentiation of hematopoietic stem cells in vivo.

Role of c-mpl in early hematopoiesis

Recently, several lines of evidence have indicated an expanded role for thrombopoietin (TPO) and its receptor, c-mpl, in hematopoiesis. In addition to being the primary physiological regulator of platelet production, it is now apparent that TPO also acts during early hematopoiesis. To futher define the role of TPO in early hematopoiesis we have identified discrete murine and human stem cell populations with respect to c-mpl expression and evaluated their potential for hematopoietic engraftment. Fluorescence-activated cell sorter analysis of enriched stem cell populations showed the presence of c-mpl expressing subpopulations. Approximately 50% of the murine fetal liver stem cell-enriched population, AA4(+)Sca+c-kit+, expressed c-mpl. Analysis of the murine marrow stem cell population LinloSca+c-kit+ showed that 70% of this population expressed c-mpl. Expression of c-mpl was also detected within the human bone marrow CD34(+)CD38(-) stem cell progenitor pool and approximately 70% of that population expressed c-mpl. To rigorously evaluate the role of TPO/c-mpl in early hematopoiesis we compared the repopulation capacity of murine stem cell populations with respect to c-mpl expression in a competitive repopulation assay. When comparing the fetal liver progenitor populations, AA4(+)Sca+c-kit+c-mpl+ and AA4(+)Sca+c-kit+c-mpl-, we found that stem cell activity segregates with c-mpl expression. This result is complemented by the observation that the LinloSca+ population of c-mpl gene-deficient mice was sevenfold less potent than LinloSca+ cells from wild-type mice in repopulating activity. The engraftment potential of the human CD34(+)CD38(-)c-mpl+ population was evaluated in a severe combined immunodeficient-human bone model. In comparison to the CD34(+) CD38(-)c-mpl- population, the CD34(+)CD38(-)c-mpl+ cells showed significantly better engraftment. These results demonstrate a physiological role for TPO and its receptor, c-mpl, in regulating early hematopoiesis.

Improving care for minority children with asthma: professional education in public health clinics

OBJECTIVE

Recent studies have shown that lack of continuing primary care for asthma is associated with increased levels of morbidity in low-income minority children. Although effective preventive therapy is available, many African-American and Latino children receive episodic treatment for asthma that does not follow current guidelines for care. To see if access, continuity, and quality of care could be improved in pediatric clinics serving low-income children in New York City, we trained staff in New York City Bureau of Child Health clinics to provide continuing, preventive care for asthma.

METHODS

We evaluated the impact of the intervention over a 2-year period in a controlled study of 22 clinics. Training for intervention clinic staff was based on National Asthma Education and Prevention Program guidelines for the diagnosis and management of asthma, and included screening to identify new cases and health education to improve family management. The intervention included strong administrative support by the Bureau of Child Health to promote staff behavior change. We hypothesized that after the intervention, clinics that received the intervention would, compared with control clinics, have increased numbers of children with asthma receiving continuing care in the clinics and increased staff use of new pharmacologic and educational treatment methods.

RESULTS

In both the first and second follow-up years, the intervention clinics had greater positive changes than control clinics on measures of access, continuity, and quality of care. For second year follow-up data these include: for access, greater rate of new asthma patients (40/1000 vs 16/1000; P < .01); for continuity, greater percentage of asthma patients returning for treatment 2 years in a row (42% vs 12%; P < .001) and greater annual frequency of scheduled visits for asthma per patient (1.85 vs .88; P < .001); and for quality, greater percentage of patients receiving inhaled beta agonists (52% vs 15%; P < .001) and inhaled antiinflammatory drugs (25% vs 2%; P < .001), and greater percentages of parents who reported receiving patient education on 12 topics from Bureau of Child Health physicians (71% vs 58%; P < .01) and nurses (61% vs 44%; P < .05).

CONCLUSION

We conclude that the intervention substantially increased the Bureau of Child Health staff's ability to identify children with asthma, involve them in continuing care, and provide them with state-of-the-art care for asthma.

Analysis of the structure of dimeric DNA catenanes by electron microscopy

We analyzed the structure of open-circular and supercoiled dimeric DNA catenanes generated by site-specific recombination in vitro. Electron microscopy of open-circular catenanes shows that the number of duplex crossings in a plane is a linear function of the number of catenane interlinks (Ca/2), and that the length of the catenane axis is constant, independent of Ca. These relationships are similar to those observed with supercoiled DNA. Statistical analyses reveal, however, that the conformations of the individual rings of the catenanes are similar to those of unlinked circles. The distribution of distances between randomly chosen points on separate rings depends strongly on Ca and is consistent with a sharp decrease in the center-of-mass separation between rings with increasing Ca. Singly linked supercoiled catenanes are seen by microscopy to be linked predominantly through terminal loops in the respective superhelices. The observations suggest that chain entropy is a major factor determining the conformation of DNA catenanes.

Variations in pediatric pneumonia and bronchitis/asthma admission rates. Is appropriateness a factor?

OBJECTIVE

To explore through a pilot study the relationship between appropriateness (medical necessity) and variations in pediatric hospital admission rates across several communities in the Boston (Mass) area for two common pediatric conditions with extremely variable admission rates: pneumonia and bronchitis/asthma.

DESIGN

We identified five communities in the greater Boston area with high, average, and below-average ratios of observed to expected admissions for the study conditions. Diagnosis-specific, criteria-based utilization review instruments were developed by community-based pediatricians and applied by trained nurse reviewers to medical records. ADMISSIONS STUDIED: All admissions for pneumonia (diagnosis related group [DRG] 91) and bronchitis/asthma (DRG 98) of study area residents younger than 18 years to participating hospitals during fiscal year 1986.

OUTCOME MEASURES

For each area, we calculated age-adjusted admission rates, age-adjusted observed to expected ratios, and rates of inappropriate admissions. We tested the hypothesis that admission rates and inappropriateness rates were directly related.

RESULTS

We deemed 9.4% of pneumonia admissions and 4.4% of bronchitis/asthma admissions inappropriate. Rates of inappropriate admissions were not significantly associated with admission rates in this local pilot study for either study condition at P < .05. However, in one community both rates were high for both conditions. Feedback of findings to the key local hospital there resulted in sharp decreases in admission rates for DRGs 91 and 98 in subsequent years.

CONCLUSIONS

Our results suggest that higher pediatric admission rates may not be associated with higher rates of inappropriateness. Further research is needed, with a larger number of communities, to differentiate practice patterns more precisely and explore patient and family preferences.

In vitro megakaryocytopoietic and thrombopoietic activity of c-mpl ligand (TPO) on purified murine hematopoietic stem cells

Recently, the ligand for c-mpl has been identified and cloned. Initial studies of this molecule indicate that it is the platelet regulatory factor, thrombopoietin (TPO). Previous work has indicated that c-mpl is expressed in very immature hematopoietic precursors and thus raised the possibility that TPO may act directly on the hematopoietic stem cell. Therefore, in these studies, we investigate the effects of TPO on hematopoietic stem cell populations isolated from the murine fetal liver and bone marrow. Cocultivation of stem cells with fetal liver stroma give rise to multilineage expansion of the stem cells but with little or no megakaryocytopoiesis. Addition of TPO to these cocultures gives significant megakaryocyte production. This production is enhanced in combination with Kit ligand or interleukin-3. The addition of TPO to stem cell suspension cultures produces a dynamic thrombopoietic system in which stem cells undergo differentiation to produce megakaryocytes and proplatelets. These experiments show that the megakaryocytopoietic and thrombopoietic activities of TPO are initiated at the level of an early progenitor cell or upon the hematopoietic stem cell.

Co-stimulation via CD28 induces activation of a refractory subset of MRL-lpr/lpr T lymphocytes

Peripheral lymphoid tissues of lpr mice contain a large proportion of TCR alpha beta/CD3+CD4-CD8- T cells that lack surface CD2 and express the B cell isoform of CD45, B220. This subset of T cells does not proliferate or produce IL-2 in response to mitogenic signals or TCR-CD3 ligation. At the same time, these abnormal T cells display several characteristics of an activated phenotype. Collectively, these properties of lpr CD4-CD8- T cells have functional parallels with anergic T cells. A critical co-stimulatory molecule implicated in the prevention of or recovery from anergy is CD28, which binds the ligand BB1/B7 on certain accessory cells. lpr CD4-CD8- T cells express normal levels of CD28 which is capable of transducing a strong proliferative signal to these cells in co-stimulation with mitogens. However, proliferation of lpr CD4-CD8- T cells in response to CD28 co-stimulation does not reach the levels observed in normal T cells stimulated under similar conditions. Stimulation with anti-CD28 mAb in conjunction with phorbol myristate acetate and ionomycin promotes cell cycling in the CD2- subset of CD4-CD8- T cells, and results in a slight induction of CD2 levels during the course of the culture period. However, the majority of cells obtained at the end of the culture period remain TCR alpha beta+ CD4-CD8-, CD2low/- and B220high, similar to freshly isolated CD4-CD8- lpr T cells. In contrast, if IL-2 is included in the cultures, a strong shift toward a CD2+ phenotype is observed by a majority of the lpr T cells. Upon repeat stimulation, these lpr CD4-CD8- T cells can now proliferate in an IL-2-dependent manner when stimulated with only anti-CD3 mAb or mitogens, in the absence of exogenous IL-2 or anti-CD28 mAb. These data show that the hyporesponsiveness of lpr CD4-CD8- T cells does not result from a lack of CD28 expression, that it is not a fixed state, and that it can be reversed by the induction of cell cycling in the presence of IL-2. These observations extend the parallels between lpr CD4-CD8- T cells and anergic T cells.

Variation in hysterectomy rates across small geographic areas of Massachusetts

OBJECTIVE

Our objective was to determine whether small-area variation in hysterectomy rates exists within Massachusetts and, if so, whether regions with persistently high or low rates can be identified.

STUDY DESIGN

By examining data derived from standardized hospital discharge forms between 1982 and 1989, we compared hysterectomy rates among 172 small geographic areas within Massachusetts. The ratios of actual to expected number of hysterectomies for each area were also computed. Statistical significance of rate variation was established by a value of p < 0.01 (chi 3 test).

RESULTS

The-hysterectomy rate per 1000 women varies fivefold across small-population areas of Massachusetts. Eight areas had persistently high and five had persistently low rates compared with the statewide average.

CONCLUSION

Possible explanations for these rate variations include indigenous population factors, supply of health care resources, income, insurance coverage, methodological problems in data analysis, and variation in professional judgment with regard to the indication for hysterectomy. Only a combination of the study of local causes of high and low rates and the study of the clinical outcomes of different treatment decisions will allow physicians to develop an informed consensus on appropriate indications for surgery.

Costimulatory signals are required for optimal proliferation of human natural killer cells

CD56dim NK cells, which comprise approximately 90% of human peripheral blood NK cells, respond to IL-2 with cytokine production, up-regulation of functionally relevant surface molecules, and augmented cytolytic activity. Nevertheless, CD56dim NK cells proliferate poorly in response to IL-2 alone. We found that other NK cell mitogens, including IL-4, IL-7, and IL-12, also induced little proliferation of CD56dim NK cells. Indeed, IL-2 stimulated at least 10-fold more NK cell proliferation than did IL-4, IL-7, or IL-12. In contrast, leukocyte-conditioned medium (LCM) induced two- to threefold greater proliferation of CD56dim NK cells than did optimal concentrations of IL-2. Although the calcium ionophore ionomycin did not stimulate proliferation by itself, it markedly augmented LCM-induced proliferation of CD56dim NK cells. Proliferation in response to either LCM alone or LCM together with ionomycin was almost completely abrogated by anti-IL-2R antibodies. Thus, IL-2 appears to be necessary but not sufficient for optimal proliferation of CD56dim NK cells. LCM-induced proliferation of ionomycin-activated CD56dim NK cells was inhibited 24% by anti-IL-1 heteroantisera and 57% by anti-TNF antisera; a combination of both antisera inhibited proliferation by 73%. Furthermore, although rIL-1 and TNF did not induce proliferation by themselves, both cytokines could augment IL-2-induced proliferation of resting or ionomycin-activated NK cells. Hence IL-1 and TNF do not appear to be primary NK cell mitogens, but rather accessory factors that can enhance IL-2-dependent NK cell proliferation. Stimulation through CD2 or CD16 Ag did not enhance LCM-induced NK cell proliferation. However, stimulation with NK-sensitive K562 cells strongly augmented CD56dim NK cell proliferation to LCM or to IL-2, IL-1, and TNF in combination. NK-resistant Daudi cells did not promote the proliferation of highly purified NK cells. Thus, NK cell proliferation may be enhanced by triggering through putative receptors for natural killing, and ionomycin may mimic such triggering. Although IL-2 by itself can induce NK cell proliferation, most NK cells resemble T and B lymphocytes in that they require multiple signals for optimal proliferation.

Costimulatory signals are required for optimal proliferation of human natural killer cells

CD56dim NK cells, which comprise approximately 90% of human peripheral blood NK cells, respond to IL-2 with cytokine production, up-regulation of functionally relevant surface molecules, and augmented cytolytic activity. Nevertheless, CD56dim NK cells proliferate poorly in response to IL-2 alone. We found that other NK cell mitogens, including IL-4, IL-7, and IL-12, also induced little proliferation of CD56dim NK cells. Indeed, IL-2 stimulated at least 10-fold more NK cell proliferation than did IL-4, IL-7, or IL-12. In contrast, leukocyte-conditioned medium (LCM) induced two- to threefold greater proliferation of CD56dim NK cells than did optimal concentrations of IL-2. Although the calcium ionophore ionomycin did not stimulate proliferation by itself, it markedly augmented LCM-induced proliferation of CD56dim NK cells. Proliferation in response to either LCM alone or LCM together with ionomycin was almost completely abrogated by anti-IL-2R antibodies. Thus, IL-2 appears to be necessary but not sufficient for optimal proliferation of CD56dim NK cells. LCM-induced proliferation of ionomycin-activated CD56dim NK cells was inhibited 24% by anti-IL-1 heteroantisera and 57% by anti-TNF antisera; a combination of both antisera inhibited proliferation by 73%. Furthermore, although rIL-1 and TNF did not induce proliferation by themselves, both cytokines could augment IL-2-induced proliferation of resting or ionomycin-activated NK cells. Hence IL-1 and TNF do not appear to be primary NK cell mitogens, but rather accessory factors that can enhance IL-2-dependent NK cell proliferation. Stimulation through CD2 or CD16 Ag did not enhance LCM-induced NK cell proliferation. However, stimulation with NK-sensitive K562 cells strongly augmented CD56dim NK cell proliferation to LCM or to IL-2, IL-1, and TNF in combination. NK-resistant Daudi cells did not promote the proliferation of highly purified NK cells. Thus, NK cell proliferation may be enhanced by triggering through putative receptors for natural killing, and ionomycin may mimic such triggering. Although IL-2 by itself can induce NK cell proliferation, most NK cells resemble T and B lymphocytes in that they require multiple signals for optimal proliferation.

CD27, a member of the nerve growth factor receptor family, is preferentially expressed on CD45RA+ CD4 T cell clones and involved in distinct immunoregulatory functions

CD27 is a disulfide-linked 120-kDa homodimer expressed on the majority of peripheral T cells at variable density that belongs to the recently defined nerve growth factor receptor family. mAb reactive with CD27 can either enhance or inhibit T cell activation, suggesting a crucial role in the process of T cell activation. We now show that CD27 is preferentially expressed on the CD45RA+CD45RO-CD29low subset of CD4 cells. CD27 expression on this subset is maintained for a prolonged period in culture after PHA activation. In contrast, CD45RA-CD45RO(+)-CD29high subset of CD4 cells express very low level of CD27, and its expression is lost within 2 wk after PHA activation. To further analyze the differential expression of CD27 on these reciprocal subsets of CD4 cells, we developed T cell clones by stimulating isolated CD4+CD45RA+ and CD4+CD45RO+ populations with PHA. T cell clones derived from cells originally CD45RA+ retained both CD45RA and CD27 expression, whereas T cell clones derived from cells originally CD45RO+ were CD45RA- and CD27-. In functional assays, IL-4 production could only be induced in CD45RA-CD27- CD4 clones by stimulation with PMA and ionomycin. Four of six CD45RA+ CD4 clones had suppressor activity in PWM-driven IgG synthesis, whereas five of six CD45RA- CD4 clones had helper activity. Of interest, the suppressor activity of CD45RA+CD27+ clones was partially blocked by pretreatment with anti-CD27 mAb (1A4). Anti-1A4 pretreatment of these T cell clones resulted in elevation of intracellular cAMP levels. Thus, CD27 appears to play a role in the function of CD45RA+CD27+ CD4 cells, and may be involved in suppressor activity of these cells at least in part via its effects on cAMP production.

CD27, a member of the nerve growth factor receptor family, is preferentially expressed on CD45RA+ CD4 T cell clones and involved in distinct immunoregulatory functions

CD27 is a disulfide-linked 120-kDa homodimer expressed on the majority of peripheral T cells at variable density that belongs to the recently defined nerve growth factor receptor family. mAb reactive with CD27 can either enhance or inhibit T cell activation, suggesting a crucial role in the process of T cell activation. We now show that CD27 is preferentially expressed on the CD45RA+CD45RO-CD29low subset of CD4 cells. CD27 expression on this subset is maintained for a prolonged period in culture after PHA activation. In contrast, CD45RA-CD45RO(+)-CD29high subset of CD4 cells express very low level of CD27, and its expression is lost within 2 wk after PHA activation. To further analyze the differential expression of CD27 on these reciprocal subsets of CD4 cells, we developed T cell clones by stimulating isolated CD4+CD45RA+ and CD4+CD45RO+ populations with PHA. T cell clones derived from cells originally CD45RA+ retained both CD45RA and CD27 expression, whereas T cell clones derived from cells originally CD45RO+ were CD45RA- and CD27-. In functional assays, IL-4 production could only be induced in CD45RA-CD27- CD4 clones by stimulation with PMA and ionomycin. Four of six CD45RA+ CD4 clones had suppressor activity in PWM-driven IgG synthesis, whereas five of six CD45RA- CD4 clones had helper activity. Of interest, the suppressor activity of CD45RA+CD27+ clones was partially blocked by pretreatment with anti-CD27 mAb (1A4). Anti-1A4 pretreatment of these T cell clones resulted in elevation of intracellular cAMP levels. Thus, CD27 appears to play a role in the function of CD45RA+CD27+ CD4 cells, and may be involved in suppressor activity of these cells at least in part via its effects on cAMP production.

Response of human natural killer (NK) cells to NK cell stimulatory factor (NKSF): cytolytic activity and proliferation of NK cells are differentially regulated by NKSF

Natural killer cell stimulatory factor (NKSF) is a 70-kD heterodimeric cytokine that was initially isolated from conditioned medium of human B lymphoblastoid cell lines. The effects of recombinant NKSF on the function of human peripheral blood NK cells were examined. NKSF directly augmented the cytolytic activity of freshly isolated NK cells. Both CD56dim and CD56bright NK cells demonstrated enhanced cytotoxicity after brief exposure to NKSF. In contrast, highly purified T lymphocytes did not exhibit major histocompatibility complex- unrestricted cytotoxicity after short-term culture with NKSF. Like interleukin 2 (IL-2), NKSF augmented the lysis of NK-sensitive, NK- resistant, and antibody-coated targets. Both NKSF and IL-2 induced marked upregulation of several NK cell adhesion molecules known to participate in cytolysis, including CD2, CD11a, and CD54. However, NKSF activates NK cells through a pathway distinct from that of IL-2, since the presence of anti-IL-2 receptor (anti-IL-2R) antibodies or IL-4 did not inhibit the effects of NKSF. NKSF by itself induced very little proliferation of resting NK cells. NK cells preactivated in vitro with IL-2 demonstrated enhanced proliferation to NKSF, but the degree of proliferation was always inferior to that induced by IL-2 alone. Moreover, NKSF strongly inhibited IL-2-induced proliferation of either resting or preactivated NK cells. This inhibition was not the result of decreased IL-2R expression, because NKSF-activated NK cells expressed higher levels of both IL-2Rs p75 and p55. Furthermore, NKSF did not inhibit the proliferation of mitogen-activated T cells, indicating a selective effect on NK cell proliferation. Human NK cells expanded in vivo by prolonged continuous infusions of IL-2 remained fully responsive to NKSF. Picomolar concentrations of NKSF were as effective as nanomolar concentrations of IL-2 in augmenting the cytolytic activity of NK cells expanded in vivo by IL-2. NKSF may play an important role in the regulation of human NK cell function, and its possible use as a therapeutic cytokine deserves further investigation.

A new technique for sheathless percutaneous intraaortic balloon catheter insertion

Intraaortic balloon counterpulsation is helpful for controlling myocardial ischemia and providing hemodynamic support, but its applicability is limited by lower extremity ischemic complications in a significant percentage of patients. We developed a new sheathless technique for percutaneous intraaortic balloon catheter insertion which reduces the effective catheter diameter. A pilot study using this new technique resulted in a 10% rate of limb ischemia, without compromise of balloon function. We conclude that this technique may be useful in reducing the incidence of limb ischemia associated with intraaortic balloon counterpulsation.

Development of a monoclonal antibody, anti-6C2, which is involved in the interaction of CD4 T helper cells and activated B cells

We have developed a mAb anti-6C2, by immunizing mice with T cell line derived from the Callithrix jacchus (common marmoset). Anti-6C2 is reactive with approximately 50% of unfractionated T cells, 50% of CD4+ cells, and 40% of CD8+ cells. Regarding CD4+ cells, anti-6C2-reactive cells substantially overlap with the CD29+CD45RO+ Th cell population. Moreover, anti-6C2 can divide these T cells into 6C2+ and 6C2- subpopulations. The CD4+CD45RO+6C2+ cells maximally respond to soluble Ag such as tetanus toxoid and provide strong helper function for PWM-driven B cell IgG synthesis. Most interestingly, anti-6C2 was also reactive against activated B cells but not resting B cells; furthermore, this epitope was inducible through activation of resting B cells or B cell line. Biochemical characterization showed that anti-6C2 precipitated two glycoproteins with the relative molecular weights of 180,000 and 95,000 from 125I-surface labeled cell lysate. Sequential immunoprecipitation studies demonstrated that these two glycoproteins were the lymphocyte function-associated antigen (LFA-1) Ag complex (CD11a/18). Significantly, although this antibody did not inhibit cytotoxic killer T cell responses and Ag-induced T cell proliferation as did conventional anti-LFA-1, it did inhibit PWM-driven B cell IgG synthesis. Because 6C2 expression was induced after B cell activation, the above results strongly suggest that the 6C2 molecule may play a role in the interaction of CD4 helper cells and activated B lymphocytes.

Development of a monoclonal antibody, anti-6C2, which is involved in the interaction of CD4 T helper cells and activated B cells

We have developed a mAb anti-6C2, by immunizing mice with T cell line derived from the Callithrix jacchus (common marmoset). Anti-6C2 is reactive with approximately 50% of unfractionated T cells, 50% of CD4+ cells, and 40% of CD8+ cells. Regarding CD4+ cells, anti-6C2-reactive cells substantially overlap with the CD29+CD45RO+ Th cell population. Moreover, anti-6C2 can divide these T cells into 6C2+ and 6C2- subpopulations. The CD4+CD45RO+6C2+ cells maximally respond to soluble Ag such as tetanus toxoid and provide strong helper function for PWM-driven B cell IgG synthesis. Most interestingly, anti-6C2 was also reactive against activated B cells but not resting B cells; furthermore, this epitope was inducible through activation of resting B cells or B cell line. Biochemical characterization showed that anti-6C2 precipitated two glycoproteins with the relative molecular weights of 180,000 and 95,000 from 125I-surface labeled cell lysate. Sequential immunoprecipitation studies demonstrated that these two glycoproteins were the lymphocyte function-associated antigen (LFA-1) Ag complex (CD11a/18). Significantly, although this antibody did not inhibit cytotoxic killer T cell responses and Ag-induced T cell proliferation as did conventional anti-LFA-1, it did inhibit PWM-driven B cell IgG synthesis. Because 6C2 expression was induced after B cell activation, the above results strongly suggest that the 6C2 molecule may play a role in the interaction of CD4 helper cells and activated B lymphocytes.