Multispecies probiotics promote perceived human health and wellbeing: insights into the value of retrospective studies on user experiences.

When taking a broader perspective on the societal impact of probiotics, engagement of end-users is important to discover unmet needs, define relevant health benefits and identify key considerations for successful implementation in daily practice. This study therefore takes a retrospective approach and analyses a database of user experiences to review the effects of four multispecies probiotic formulations. The user experiences were analysed in a dependent sample manner (without control group) and complement previous randomised controlled trials that have been performed with the formulations. The database consisted of 584 evaluable user experiences regarding the impact of probiotic supplementation on perceived quality of life (QoL), gastrointestinal (GIT) symptoms and reported stool consistency after two weeks of consumption. Two different scales were used (n=344 in a 5-point scale; n=240 in a 10-point scale), which are presented as separate analyses. In the combined population of the 5-point-scale questionnaire, a significant increase in perceived QoL and a significant reduction in perceived GIT symptoms was observed. Descriptive summaries also indicate that diarrhoea- and constipation-like stool patterns are reduced following supplementation. Moreover, half of participants indicated that probiotic supplementation had a positive effect on their unmet medical need, and 64% of users were likely to continue using the product. Similar results were observed in the 10-point scale questionnaire. Considering the clinical relevance of probiotic supplementation in specific target groups, subgroup analyses were performed on participants who consumed the products for diarrhoea, constipation, Inflammatory Bowel Disease, Irritable Bowel Syndrome, and antibiotic usage. Overall, findings support the potential of probiotics to advance perceived human health and support the daily wellbeing of users. This systematic analysis of user experiences thereby contributes to the external validity of studies evaluating clinical effects of probiotics and increases knowledge on their societal impact.

gp39-CD40 interactions are essential for germinal center formation and the development of B cell memory.

gp39, the ligand for CD40 expressed on activated CD4+ T helper cells, is required for the generation of antibody responses to T-dependent (TD) antigens. Treatment of mice with anti-gp39 in vivo inhibits both primary and secondary antibody formation to TD, but not T-independent antigens. However, the role of this receptor-ligand pair in the development of germinal centers and the generation of B cell memory is as yet undefined. Using an antibody to gp39, this study examines the in vivo requirement for gp39-CD40 interactions in the induction of germinal center formation, as well as in the generation of B cell memory. Animals were immunized, treated in vivo with anti-gp39, and evaluated using immunohistochemical staining for the presence of splenic germinal centers 9-11 d after immunization. The results demonstrate that the formation of germinal centers was completely inhibited as a result of treatment with anti-gp39. Moreover, adoptive transfer experiments demonstrate that the generation of antigen-specific memory B cells is also inhibited as a consequence of blocking gp39-CD40 interactions. Taken together, the data demonstrate that gp39-CD40 interactions are critical not only for the generation of antibody responses, but also in the development of B cell memory.

In vivo CD40-gp39 interactions are essential for thymus-dependent humoral immunity. I. In vivo expression of CD40 ligand, cytokines, and antibody production delineates sites of cognate T-B cell interactions.

T-B cell interactions have a central role in the development of antibody responses. Upon activation, T helper (Th) cells express the ligand for CD40, gp39, which is essential for Th cell-dependent B cell activation. The cytokines produced by activated Th cells have a regulatory role in B cell differentiation. In this study, we investigated, using immunohistochemical techniques, the in vivo time course and localization of gp39 expression and cytokine production in relation to the specific antibody production. Both the immunization with keyhole limpet hemocyanin (KLH), a thymus-dependent (TD) antigen, and trinitrophenyl (TNP)-Ficoll, a thymus-independent type 2 (TI-2) antigen, induced Th cells to express gp39. The expression of gp39 was restricted to Th cells in the outer periarteriolar lymphocyte sheaths (outer-PALS) and around the terminal arterioles (TA). Incidentally, gp39+ Th cells were found in the corona of follicles, whereas gp39+ cells were never found in the germinal centers or marginal zones of the spleen. Maximum frequencies of gp39+ cells were observed 3 and 4 d after primary and secondary immunization with KLH. After injection of TNP-Ficoll, a marked increase in gp39+ cells was observed, confirming previous observations that activated T cells are involved in TI-2 antibody responses. Analysis of the in vivo cytokine production revealed that interleukin 2 (IL-2)-, IL-4- and interferon gamma (IFN-gamma)-producing cells (IFN-gamma-PC) developed according to similar kinetics as observed for gp39+ cells. IL-2-PC and IL-4-PC were present in higher frequencies as were IFN-gamma-PC in the immune response against TNP-KLH. Double staining experiments revealed gp39+ Th cells producing IL-2, IL-4, or IFN-gamma, suggesting that these cells were involved in both the initial activation as well as the differentiation process of B cells into antibody-forming cells. Dual immunohistochemical analysis revealed gp39+ T cells and cytokine-PC in close proximity to antigen-specific, antibody-forming B cells. In conclusion, this study shows that in vivo gp39 is expressed on activated Th cells after immunization with TD and TI-2 antigens. Furthermore, the time course and compartmentalization of gp39+ expression, cytokine production and antibody formation after immunization suggest that cognate T-B cell interactions and T cell-regulated B cell differentiation occur in the outer-PALS and around the TA of the spleen.

An essential role for gp39, the ligand for CD40, in thymic selection.

The interactions between CD40 on B cells and its ligand gp39 on activated T helper cells are known to be essential for the development of thymus-dependent humoral immunity. However, CD40 is also functionally expressed on thymic epithelial cells and dendritic cells, suggesting that gp39-CD40 interactions may also play a role in thymic education, the process by which self-reactive cells are deleted from the T cell repertoire. Six systems of negative selection were studied for their reliance on gp39-CD40 interactions to mediate negative selection. In all cases, when the antigen/superantigen was endogenously expressed (in contrast to exogenously administered), negative selection was blocked by loss of gp39 function. Specifically, blockade of gp39-CD40 interactions prevented the deletion of thymocytes expressing V beta 3, V beta 11, and V beta 12, specificities normally deleted in BALB/c mice because of the endogenous expression of minor lymphocyte-stimulating determinants. Independent verification of a role of gp39 in negative selection was provided by studies in gp39-deficient mice where alterations in T cell receptor (TCR) V beta expression were also observed. Studies were also performed in the AND TCR transgenic (Tg) mice, which bear the V alpha 11, V beta 3 TCR and recognize both pigeon cytochrome c (PCC)/IEk and H-2As. Neonatal administration of anti-gp39 to AND TCR Tg mice that endogenously express H-2As or endogenously produce PCC prevented the deletion of TCR Tg T cells. In contrast, deletion mediated by high-dose PCC peptide antigen (administered exogenously) in AND TCR mice was unaltered by administration of anti-gp39. In addition, deletion by Staphylococcus enterotoxin B in conventional mice was also unaffected by anti-gp39 administration. gp39 expression was induced on thymocytes by mitogens or by antigen on TCR Tg thymocytes. Immunohistochemical analysis of B7-2 expression in the thymus indicated that, in the absence of gp39, B7-2 expression was substantially reduced. Taken together, these data suggest that gp39 may influence negative selection through the regulation of costimulatory molecule expression. Moreover, the data support the hypothesis that, for negative selection to some endogenously produced antigens, negative selection may be dependent on TCR engagement and costimulation.

Prevalence of viral respiratory infections amongst asthmatics: Results of a meta-regression analysis.

Viral respiratory infections (VRI) can act as triggers for acute asthma exacerbations and contribute significantly to asthma-related healthcare costs. Knowing the patterns of viruses amongst asthmatics can be useful in treating and preventing these exacerbations and help decrease the burden they impose on patients and healthcare systems. We aimed to quantify the viral prevalence in asthmatics presenting with exacerbations and identify influencing factors. A meta-analysis with a systematic search was conducted. Random-effect analysis was performed to quantify prevalence of viruses. A meta-regression was conducted to explain sources of heterogeneity and identify confounding factors. A VRI was detected in 52%-65% of the cases, and the detection rate was higher in children compared to adults. Rhinovirus was most often detected [51-71%], followed by respiratory syncytial virus [8-18%], influenza virus [7-15%], human parainfluenza virus [4-11%] and metapneumovirus virus [3-9%]. Meta-regression showed that the variables age and hemisphere contributed to the heterogeneity observed and were significantly associated with the detection of viruses in asthmatics. The climate variable reached significance for RSV and indicated a higher detection rate of viruses in asthmatics living in temperate compared to tropical regions. Besides age, geographic location and related variables significantly influence to what extent respiratory viruses are detected amongst asthmatics with exacerbations. Our results indicate that health authorities should adopt region- and population specific prevention and treatment strategies. Prevention and detection of viral respiratory infections in asthmatics could reduce asthma related disease burden and decrease antibiotic misuse.

On the importance of intraindividual variation in nutritional research.

Nutritional intervention studies, like those with pre- and probiotics, are often hampered by low effect sizes, reducing the power to demonstrate potential efficacy. Here, we perform computer simulations of a hypothetical clinical trial using such an intervention in order to elucidate determining factors that can be influenced in order to optimise the statistical power. Our simulations demonstrate that steering the study population towards a low intraindividual variation dramatically improves statistical power. A more than 10-fold decrease of number-to-treat could be reached. Also, a careful balancing between the number of subjects and measurements per subject, in combination with possible stratification of the subjects into responders and non-responders, based on inherent intraindividual variation, improves the likelihood to reach statistically significant results. Our results also show that traditional dogmas, with respect to clinical trials, i.e. aiming at low interindividual variation and a high number (n) of study participants, should be re-evaluated in favour of reducing intraindividual variation. This reduction in intraindividual variation could be achieved by maintaining a steady lifestyle, including dietary habits among others, within the timeframe of the intervention study.

Dealing with the remaining controversies of probiotic safety.

A clear safety profile of probiotics in clinical practice is essential in decision-making for all stakeholders and regulators. Probiotics have been investigated in different target populations, conditions and age groups. This also includes the use of probiotics in critically ill patients. Despite promising results reported with the use of probiotics and synbiotics, there is still a lively discussion regarding the proper and safe use of probiotics among physicians, researchers and regulators. This doubt and debate was sparked by the high incidence in mortality reported in a study with critically ill patients. Whereas no causal relationship has been established since, safety of probiotic has been questioned. In response, an overwhelming body of evidence suggesting that probiotics are safe has been compiled. Moreover, data indicates that probiotics reduce the number of adverse events compared to the control. However, due to a lack of standardised safety reporting in clinical studies, a strong evidence base on probiotic safety remains to be established. Here, we will discuss: (1) the rationale for using probiotics in the critically ill; (2) what happened during the Dutch Pancreatitis trial; (3) what are the known safety risks of probiotics based on the available data; and finally (4) how standardisation in safety reporting can drive probiotic innovation. Building a strong safety profile for probiotic strains will solidify its use in individuals that can benefit the most from microbial modulation.

Towards improved process efficiency in vaccine innovation: The Vaccine Innovation Cycle as a validated, conceptual stage-gate model.

Continuing investments in vaccine innovation are insufficiently translated into market entries of novel vaccines. This innovation paradox is in part caused by stakeholders lacking complete understanding of the complex array of steps necessary for vaccine development and collaboration difficulties between the wide variety of stakeholders involved. Models providing cross-domain understanding can improve collaboration but currently lack both comprehensibility and granularity to enable a prioritized view of activities and criteria. Key opinion leaders (KOLs) were asked to contribute to the definition of a vaccine innovation cycle (VIC). In a first step, 18 KOLs were interviewed on the stages (activities and results) and gates (evaluation criteria and outcomes) of vaccine innovation. This first description of the VIC was subsequently validated and refined through a survey among 46 additional KOLs. The VIC identifies 29 distinct stages and 28 corresponding gates, distributed in ten different but integrated workstreams, and comprehensibly depicted in a circular innovation model. Some stage-gates occur at defined moments, whereas the occurrence and timing of other stage-gates is contingent on a variety of contextual factors. Yet other stage-gates continuously monitor internal and external developments. A gap-overlap analysis of stage-gate criteria demonstrated that 5 out of 11 criteria employed by vaccine developers correspond with criteria employed by competent (regulatory) authorities. The VIC provides a comprehensive overview of stage-gates throughout the value chain of vaccine innovation. Its cyclical nature highlights the importance of synchronizing with unmet needs and market changes, and conceptualizes the difference between incremental and radical vaccine innovation. Knowledge on the gap between internal and external criteria will enhance the viability of newcomers to the field. The VIC can be used by stakeholders to improve understanding and communication in forming collaborative alliances and consortia. Such a boundary-spanning function may contribute to the reduction of process inefficiencies, especially in public-private partnerships.

Immunodeficiency due to a faulty interaction between T cells and B cells.

The identification of the ligand for CD40, gp39, which is expressed on the membrane of activated CD4+ T-helper cells, has sparked intense investigation into the roles of this molecule in physiological B-cell activation. Recently, it has become clear that some human immunodeficiencies, such as X-linked hyper IgM syndrome and common variable immunodeficiency are linked to mutations in the gp39 gene or are a result of defective expression of gp39, leading to suboptimal, or a lack of, B-cell activation by T-helper cells.

The moderating role of absorptive capacity and the differential effects of acquisitions and alliances on Big Pharma firms' innovation performance.

In the context of increased pharmaceutical innovation deficits and Big Pharma blockbusters' patent expirations, this paper examines the moderating role of firms' absorptive capacity in external innovation activities of Big Pharma firms. The study indicates a rising interest of Big Pharma in acquisitions of and alliances with biotechnology companies. Unfortunately, this increased interest is not reflected in the number of new drugs generated by Big Pharma. We find that acquisitions of biotech companies have negatively affected Big Pharma firms' innovation performance on average but these acquisitions might have a positive effect at higher levels of acquiring firms' absorptive capacity. Moreover, also acquisitions of pharma companies and alliances with biotech companies only have a positive effect on innovation performance at sufficiently high levels of absorptive capacity. The moderating role of absorptive capacity implicates that a tight integration of internal R&D efforts and (unrelated) external knowledge is crucial for harnessing complementarity effects.

Barriers to innovation in human rabies prophylaxis and treatment: A causal analysis of insights from key opinion leaders and literature.

Rabies is an essentially 100% fatal, zoonotic disease, caused by Lyssaviruses. Currently, the disease is vaccine-preventable with pre- and post-exposure prophylaxis (PrEP and PEP). Still, rabies virus is estimated to cause up to 60,000 human deaths annually, of which the vast majority occurs in rural Asia and Africa, due to the inaccessibility of prophylaxis and non-existence of treatment. Despite these unmet clinical needs, rabies control mainly focuses on the sylvatic reservoir and drug innovation receives relatively little attention compared to other neglected tropical diseases (NTDs). As such, the lag of innovation in human rabies prophylaxis and treatment cannot be explained by limited return on investment alone. Strategies countering rabies-specific innovation barriers are important for the acceleration of innovation in human rabies prophylaxis and treatment. Barriers throughout society, science, business development and market domains were identified through literature review and 23 semi-structured interviews with key opinion leaders worldwide. A subsequent root cause analysis revealed causal relations between innovation barriers and a limited set of root causes. Finally, prioritization by experts indicated their relative importance. Root causes, which are fundamental to barriers, were aggregated into four types: market and commercial, stakeholder collaboration, public health and awareness, and disease trajectory. These were found in all domains of the innovation process and thus are relevant for all stakeholders. This study identifies barriers that were not previously described in this specific context, for example the competition for funding between medical and veterinary approaches. The results stress the existence of barriers beyond the limited return on investment and thereby explain why innovation in human rabies medication is lagging behind NTDs with a lower burden of disease. A re-orientation on the full spectrum of barriers that hinder innovation in rabies prophylaxis and treatment is necessary to meet unmet societal and medical needs.

The effect of elimination of macrophages on the tissue distribution of liposomes containing [3H]methotrexate.

In the present study the tissue distribution of [3H]methotrexate was studied after intravenous injection of [3H]methotrexate-containing liposomes in normal and macrophage-depleted mice. Elimination of macrophages was performed by treatment with dichloromethylene diphosphonate- (DMDP)-containing liposomes. After thorough elimination of the macrophages from spleen and liver, by two intravenous injections of DMDP liposomes 6 and 4 days before tissue distribution studies, we found dramatic changes in the localization pattern of [3H]methotrexate liposomes in the blood, due to a decreased uptake of [3H]methotrexate liposomes by the DMDP liposome-treated liver. Because of the absence of these macrophages that are able to clear the blood of liposomes, and because of the resulting higher blood level of liposomes, we found an enhanced uptake of [3H]methotrexate liposomes by the spleen. It may be concluded that, in the spleen, apart from uptake of liposomes by macrophages, at least one other mechanism is responsible for the clearance of liposomes from the circulation. When comparing cholesterol-rich with cholesterol-poor liposomes, we found basically the same results, although uptake of cholesterol-rich liposomes by macrophages was smaller than that of cholesterol-poor liposomes, as found in several other studies. We suggest that pretreatment with DMDP liposomes can help to maintain a high level of intravenous-injected liposome-entrapped material in the blood, which otherwise would be removed by macrophages.

Epitope prediction and confirmation for the human androgen receptor: generation of monoclonal antibodies for multi-assay performance following the synthetic peptide strategy.

The human androgen receptor (hAR) is an important regulatory protein particularly in male sexual differentiation. The investigation of hAR functionality has been hampered by the lack of AR specific monoclonal antibodies recognizing the functional domains of the receptor. Therefore production of high affinity mono-specific polyclonal (PAbs) and monoclonal antibodies (MAbs) directed to the hAR was initiated following the synthetic peptide (SP) strategy. Five hAR specific peptides were selected on the basis of their predicted antigenic properties avoiding homology with other steroid hormone receptors. Peptide specific polyclonal antisera were obtained following selected immunization protocols. Mono-specific polyclonal antibody responses were elicited to all peptides in mice and rabbits. Crossreactivity of the peptide specific antisera with the native hAR in various biochemical assays was observed with two out of five peptides. Peptide SP61 (hAR residues 301-320) was used for the generation site-directed MAbs specific for the hAR. Specificity for the hAR was established by immunoprecipitation, immune-complex density gradient centrifugation and immunohistochemistry on human prostate tissue sections. The multi-assay performance of the selected high affinity antibodies proved the usefulness of the straight forward peptide approach and opens a wide field of possible biochemical and physiological investigations into questions related to androgen action.

Functions of CD40 and its ligand, gp39 (CD40L).

Initially, a role for the interaction between CD40, expressed on B cells, and gp39 (CD40L), expressed on activated T cells, has been defined in humoral immunity. CD40-CD40L interaction is an essential signal for B cell proliferation, expression of activation markers, immunoglobulin production, and isotype switching. CD40-CD40L interaction is also required for formation of B memory cells and germinal centers, and signaling through CD40 prevents apoptosis of germinal center B cells. Defective expression of CD40L in humans leads to an inability to produce isotypes other than IgM (hyper IgM syndrome), and to an absence of germinal centers. More recent evidence indicates an expansion of the role of the CD40-CD40L axis in cellular interactions beyond antibody formation. Induced expression of CD40 on monocytes can lead to CD40L-activated monocyte effector mechanisms. In addition, CD40-CD40L interactions are crucially involved in development of autoimmune disease in a number of animal models. CD40-CD40L interactions also impact on growth regulation of certain carcinomas. Manipulation of CD40L has also been used to develop novel strategies for long-term antigen-specific tolerization of peripheral T cells. Finally, the CD40-CD40L axis is involved in thymic selection. Following is a comprehensive overview of CD40L-CD40 interactions in physiological and pathogenic cellular responses and a discussion of the therapeutic ramifications of these interactions.

Immunological functions and in vivo cell-cell interactions of T cells in the spleen.

The spleen is an important lymphoid organ, involved in immune responses against all types of antigen that appear in the circulation. Its complex anatomical organization, with distinct compartments containing specialized cell types, provides a microenvironment which allows different cell-cell interactions and determines the direction of developing immune responses. In this review we evaluate the vast amount of in vitro data dealing with antigen presentation, cell-cell interactions, T and B cell activation, and the immunoregulatory role of cytokines, as suggested to be involved in immune responses. As a basis for understanding of in vivo processes, these in vitro data will be related to discrete phenomena of in vivo immune responses, such as antigen localization/trapping, cell migration patterns of immunocompetent cells, cytokine production, and antibody formation in the different compartments of the spleen. Finally, we try to bring order to the sequence of events that occur in the spleen after antigenic challenge by presenting an in vivo model for T cell dependent and T cell independent immune responses.

Safety of probiotics and synbiotics in children under 18 years of age.

This study aimed to systematically evaluate safety of probiotics and synbiotics in children ageing 0-18 years. This study is the third and final part in a safety trilogy and an update is provided using the most recent available clinical data (2008-2013) by means of the Common Terminology Clinical Adverse Events (CTCAE version 4.0) classification. Safety aspects are represented and related to number of participants per probiotic strain/culture, study duration, dosage, clinical condition and selected afflictions. Analysis of 74 clinical studies indicated that probiotic and/or synbiotic administration in children is safe with regard to the specific evaluated strains, dosages and duration. The population of children include healthy, immune compromised and obese subjects, as well as subjects with intestinal disorders, infections and inflammatory disorders. This study revealed no major safety concerns, as the adverse events (AEs) were unrelated, or not suspected to be related, to the probiotic or synbiotic product. In general the study products were well tolerated. Overall, AEs occurred more frequent in the control arm compared to children receiving probiotics and/or synbiotics. Furthermore, the results indicate inadequate reporting and classification of AEs in the majority of the studies. In addition, generalizability of conclusions are greatly limited by the inconsistent, imprecise and potentially incomplete reporting as well as the variation in probiotic strains, dosages, administration regimes, study populations and reported outcomes.

Market implementation of the MVA platform for pre-pandemic and pandemic influenza vaccines: A quantitative key opinion leader analysis.

A quantitative method is presented to rank strengths, weaknesses, opportunities, and threats (SWOT) of modified vaccinia virus Ankara (MVA) as a platform for pre-pandemic and pandemic influenza vaccines. Analytic hierarchy process (AHP) was applied to achieve pairwise comparisons among SWOT factors in order to prioritize them. Key opinion leaders (KOLs) in the influenza vaccine field were interviewed to collect a unique dataset to evaluate the market potential of this platform. The purpose of this study, to evaluate commercial potential of the MVA platform for the development of novel generation pandemic influenza vaccines, is accomplished by using a SWOT and AHP combined analytic method. Application of the SWOT-AHP model indicates that its strengths are considered more important by KOLs than its weaknesses, opportunities, and threats. Particularly, the inherent immunogenicity capability of MVA without the requirement of an adjuvant is the most important factor to increase commercial attractiveness of this platform. Concerns regarding vector vaccines and anti-vector immunity are considered its most important weakness, which might lower public health value of this platform. Furthermore, evaluation of the results of this study emphasizes equally important role that threats and opportunities of this platform play. This study further highlights unmet needs in the influenza vaccine market, which could be addressed by the implementation of the MVA platform. Broad use of MVA in clinical trials shows great promise for this vector as vaccine platform for pre-pandemic and pandemic influenza and threats by other respiratory viruses. Moreover, from the results of the clinical trials seem that MVA is particularly attractive for development of vaccines against pathogens for which no, or only insufficiently effective vaccines, are available.

Improving the bowel habits of elderly residents in a nursing home using probiotic fermented milk.

Our aim was to determine whether a fermented milk drink containing probiotics could improve the bowel habits of frail elderly individuals living in a nursing home. A total of 135 participants were enrolled in this pilot study. The bowel habits (stool quality and bowel movements) were recorded by nursing staff during a baseline period of 3 weeks. After this period participants received daily a fermented milk drink containing minimally 6.5×10(9) colony forming units of Lactobacillus casei Shirota (LcS) for 6 weeks. During this period, bowel habits were recorded and compared to baseline period. Forty-four participants (74-99 years old) were compliant and used for analysis. Consumption of fermented milk containing LcS significantly increased the percentage of ideal stool types per week (P<0.01), lowered the percentage of constipation stool types per week (P<0.01) and significantly lowered the percentage of diarrhoea stool types per week (P=0.016) as compared to the baseline period. The study product had no significant effect on bowel movements. During the study, no changes in laxative usage or adverse events associated with the study product were reported. Our results suggest that a fermented milk containing LcS significantly improves the bowel habits of frail elderly residents in a nursing home. These promising results should be further substantiated by a confirmatory study.

Immunocytochemical determination of antigen and epitope specificity of HIV-1-specific B cells in lymph-node biopsies from HIV-1-infected individuals.

Knowledge about B-cell dysfunction and HIV-specific antibody production is necessary for the understanding of both HIV-1-related immunopathology and the (vaccine-induced) humoral immunity involved in protection against AIDS. This paper describes the application of recently developed methods to detect epitope specificity of B cells in lymph-node biopsies with antigen-enzyme conjugates. Cryosections of five lymph-node biopsies from HIV-1-infected individuals and four control tissues were stained with a panel of HIV-1 antigen-enzyme conjugates: recombinant HIV-1 proteins (gp 160, gp 120 and p24), labelled with peroxidase, and synthetic peptides representing neutralizing epitopes from gp120 and gp41, labelled with alkaline phosphatase. Antibody-forming cells (AFCs) were detected in all the HIV-1-infected biopsies with gp160, gp120 and/or p24, in numbers up to 350 per section. AFCs producing specific antibodies against peptide 101 (SP 101), representing the neutralizing epitope 586-608 of gp41, were detected in one patient. These techniques allow correlation of in vivo function of B cells with lymph-node pathology, clinical stage of the disease and serological data. Their potential for the elucidation of HIV-related immunopathogenesis and the development of vaccines is discussed.

Long-term genetic modification of rhesus monkey hematopoietic cells following transplantation of adenoassociated virus vector-transduced CD34+ cells.

We have explored the potential of recombinant adenoassociated virus (AAV) vectors for gene transfer of the human beta-globin gene and the genetic modification of primate pluripotent hematopoietic stem cells (P-PHSCs). Transduction of P-PHSCs was tested in a preclinical bone marrow transplantation model in rhesus monkeys. CD34+ cells were transduced ex vivo and autologously transplanted without prior selection into irradiated rhesus monkeys. Vector-transduced peripheral blood mononuclear cells and granulocytes were present in the circulation for more than 15 months after transplantation. Approximately 1 in 10(5) cells in the circulation was vector modified. The vector was detected in the bone marrow, in granulocytes, and in purified populations of B and T cells, thus demonstrating multilineage repopulation by vector-transduced stem cells. Comparison of transduction protocols suggested that short-term culture of P-PHSCs enhances transduction and subsequent repopulation by rAAV-transduced cells. These results demonstrate that rAAV vectors can be used for the permanent genetic modification of a rhesus monkey hematopoietic system in the absence of selective pressure.