Immunological Outcomes of New Tuberculosis Vaccine Trials: WHO Panel Recommendations

Willem Hanekom and colleagues make recommendations on assay harmonization for novel tuberculosis vaccine trials

rBCG Induces Strong Antigen-Specific T Cell Responses in Rhesus Macaques in a Prime-Boost Setting with an Adenovirus 35 Tuberculosis Vaccine Vector

BACKGROUND: BCG vaccination, combined with adenoviral-delivered boosts, represents a reasonable strategy to augment, broaden and prolong immune protection against tuberculosis (TB). We tested BCG (SSI1331) (in 6 animals, delivered intradermally) and a recombinant (rBCG) AFRO-1 expressing perfringolysin (in 6 animals) followed by two boosts (delivered intramuscullary) with non-replicating adenovirus 35 (rAd35) expressing a fusion protein composed of Ag85A, Ag85B and TB10.4, for the capacity to induce antigen-specific cellular immune responses in rhesus macaques (Macaca mulatta). Control animals received diluent (3 animals). METHODS AND FINDINGS: Cellular immune responses were analyzed longitudinally (12 blood draws for each animal) using intracellular cytokine staining (TNF-alpha, IL-2 and IFN-gamma), T cell proliferation was measured in CD4(+), CD8alpha/beta(+), and CD8alpha/alpha(+) T cell subsets and IFN-gamma production was tested in 7 day PBMC cultures (whole blood cell assay, WBA) using Ag85A, Ag85B, TB10.4 recombinant proteins, PPD or BCG as stimuli. Animals primed with AFRO-1 showed i) increased Ag85B-specific IFN-gamma production in the WBA assay (median >400 pg/ml for 6 animals) one week after the first boost with adenoviral-delivered TB-antigens as compared to animals primed with BCG (<200 pg/ml), ii) stronger T cell proliferation in the CD8alpha/alpha(+) T cell subset (proliferative index 17%) as compared to BCG-primed animals (proliferative index 5% in CD8alpha/alpha(+) T cells). Polyfunctional T cells, defined by IFN-gamma, TNF-alpha and IL-2 production were detected in 2/6 animals primed with AFRO-1 directed against Ag85A/b and TB10.4; 4/6 animals primed with BCG showed a Ag85A/b responses, yet only a single animal exhibited Ag85A/b and TB10.4 reactivity. CONCLUSION: AFRO-1 induces qualitatively and quantitatively different cellular immune responses as compared with BCG in rhesus macaques. Increased IFN-gamma-responses and antigen-specific T cell proliferation in the CD8alpha/alpha+ T cell subset represents a valuable marker for vaccine-take in BCG-based TB vaccine trials

Is Nef the elusive cause of HIV-associated hematopoietic dysfunction?

HIV-associated hematological abnormalities involve all lineages of blood cells, thus implying that the virus impairs the function of early HSCs. However, the underlying mechanisms of this defect are unknown, particularly since HSCs are largely resistant to HIV-1 infection. In this issue of the JCI, Prost and colleagues show that the viral accessory protein Negative factor (Nef) plays a potentially critical role in the pathogenesis of HIV/SIV-associated hematopoietic dysfunction by affecting the clonogenic potential of HSCs (see the related article beginning on page 1765). Soluble Nef induces PPARγ in uninfected HSCs, thereby suppressing the expression of STAT5A and STAT5B, two factors necessary for proper HSC function. The identification of this novel activity of extracellular Nef defines a new mechanism of HIV/SIV pathogenesis and suggests that approaches aimed at increasing STAT5A and STAT5B expression may be considered in HIV-infected individuals with prominent hematological abnormalities. The results also raise the question of whether dysregulation of hematopoiesis by extracellular Nef plays a role in the development of T cell immunodeficiency and the high levels of chronic immune activation associated with AIDS

Human leukocyte antigens A*3001 and A*3002 show distinct peptide-binding Patterns of the Mycobacterium tuberculosis protein TB10.4 : consequences for immune recognition

High-tuberculosis (TB)-burden countries are located in sub-Saharan Africa. We examined the frequency of human leukocyte antigen (HLA) alleles, followed by recombinant expression of the most frequent HLA-A alleles, i.e., HLA-A*3001 and HLA-A*3002, to study differences in mycobacterial peptide presentation and CD8 T-cell recognition. We screened a peptide library (9-mer peptides with an 8-amino-acid overlap) for binding, affinity, and off-rate of the Mycobacterium tuberculosis-associated antigen TB10.4 and identified only three TB10.4 peptides with considerable binding to HLA-A*3001. In contrast, 22 peptides bound to HLA-A*3002. This reflects a marked difference in the binding preference between the two alleles, with A*3002 tolerating a more promiscuous peptide-binding pattern and A*3001 accommodating only a very selective peptide repertoire. Subsequent analysis of the affinity and off-rate of the binding peptides revealed a strong affinity (8 nM to 7 M) and moderate off-rate (20 min to 3 h) for both alleles. Construction of HLA-A*3001 and HLA-A*3002 tetramers containing selected binding peptides from TB10.4, including a peptide which was shared among both alleles, QIMYNYPAM (TB10.43–11), allowed us to enumerate epitope-specific T cells in HLA-A*3001- and HLA-A*3002-typed patients with active TB. HLA-A*3001 and HLA-A*3002 major histocompatibility complex-peptide complexes were recognized in individuals with active TB, irrespective of their homozygous HLA-A*3001 or HLA-A*3002 genetic background. The antigen-specific T cells exhibited the CD45RA CCR7 precursor phenotype and the interleukin- 7 receptor (CD127), which were different from the phenotype and receptor exhibited by the parental CD8 T-cell population

Human Leukocyte Antigens A*3001 and A*3002 Show Distinct Peptide-Binding Patterns of the Mycobacterium tuberculosis

High-tuberculosis (TB)-burden countries are located in sub-Saharan Africa. We examined the frequency of human leukocyte antigen (HLA) alleles, followed by recombinant expression of the most frequent HLA-A alleles, i.e., HLA-A*3001 and HLA-A*3002, to study differences in mycobacterial peptide presentation and CD8(+) T-cell recognition. We screened a peptide library (9-mer peptides with an 8-amino-acid overlap) for binding, affinity, and off-rate of the Mycobacterium tuberculosis-associated antigen TB10.4 and identified only three TB10.4 peptides with considerable binding to HLA-A*3001. In contrast, 22 peptides bound to HLA-A*3002. This reflects a marked difference in the binding preference between the two alleles, with A*3002 tolerating a more promiscuous peptide-binding pattern and A*3001 accommodating only a very selective peptide repertoire. Subsequent analysis of the affinity and off-rate of the binding peptides revealed a strong affinity (8 nM to 7 μM) and moderate off-rate (20 min to 3 h) for both alleles. Construction of HLA-A*3001 and HLA-A*3002 tetramers containing selected binding peptides from TB10.4, including a peptide which was shared among both alleles, QIMYNYPAM (TB10.4(3-11)), allowed us to enumerate epitope-specific T cells in HLA-A*3001- and HLA-A*3002-typed patients with active TB. HLA-A*3001 and HLA-A*3002 major histocompatibility complex-peptide complexes were recognized in individuals with active TB, irrespective of their homozygous HLA-A*3001 or HLA-A*3002 genetic background. The antigen-specific T cells exhibited the CD45RA(+) CCR7(+) precursor phenotype and the interleukin-7 receptor (CD127), which were different from the phenotype and receptor exhibited by the parental CD8(+) T-cell population

The Role of Interleukin-converting Enzyme in Fas-mediated Apoptosis in HIV-1 Infection

Apoptosis of CD4 � lymphocytes is partially responsible for the depletion of these cells in HIV-infected individuals. CD4 � lymphocytes from HIV-1–infected patients express higher membrane levels of the Fas receptor, and are particularly susceptible to apoptosis after Fas triggering. IL-1�– converting enzyme (ICE) is a key enzyme of the apoptotic machinery involved in Fas-mediated apoptosis of normal lymphocytes. The role of ICE in mediating the increased susceptibility of CD4 � lymphocytes from HIV-1–infected patients to apoptosis has not been examined. In this study, we found that ICE mRNA was present in T cells from both HIV-1–infected patients and controls. Active ICE proteins, p10 and p20, were demonstrated by immunoblot in lymphocytes from HIV-1–infected patients and in normal lymphocyte

EXPERTS’ PERCEIVED PATIENT BURDEN AND OUTCOMES OF KNEE-ANKLE-FOOT-ORTHOSES (KAFOs) VS. MICROPROCESSOR-STANCE-AND-SWING-PHASE-CONTROLLED-KNEE-ANKLE-FOOT ORTHOSES (MP-SSCOs)

BACKGROUND: Patients with neuromuscular knee-instability assisted with orthotic devices experience problems including pain, falls, mobility issues and limited engagement in daily activities. OBJECTIVES: The aim of this study was to analyse current real-life burden, needs and orthotic device outcomes in patients in need for advanced orthotic knee-ankle-foot-orthoses (KAFOs). METHODOLOGY: An observer-based semi-structured telephone interview with orthotic care experts in Germany was applied. Interviews were transcribed and content-analysed. Quantitative questions were analysed descriptively. FINDINGS: Clinical experts from eight centres which delivered an average of 49.9 KAFOs per year and 13.3 microprocessor-stance-and-swing-phase-controlled-knee-ankle-foot orthoses (MP-SSCOs) since product availability participated. Reported underlying conditions comprised incomplete paraplegia (18%), peripheral nerve lesions (20%), poliomyelitis (41%), post-traumatic lesions (8%) and other disorders (13%). The leading observed patient burdens were “restriction of mobility” (n=6), followed by “emotional strain” (n=5) and “impaired gait pattern” (n=4). Corresponding results for potential patient benefits were seen in “improved quality-of-life” (n=8) as well as “improved gait pattern” (n=8) followed by “high reliability of the orthosis” (n=7). In total, experts reported falls occurring in 71.5% of patients at a combined annual frequency of 7.0 fall events per year when using KAFOs or stance control orthoses (SCOs). In contrast, falls were observed in only 7.2 % of MP-SSCO users. CONCLUSION: Advanced orthotic technology might contribute to better quality of life of patients, improved gait pattern and perceived reliability of orthosis. In terms of safety a substantial decrease in frequency of falls was observed when comparing KAFO and MP-SSCO users. Layman's Abstract Patients who are not able to control the muscles of their legs may need to wear a brace to improve their ability to walk. However, some users are reporting problems including pain, falls, mobility issues and limited engagement in daily activities. The aim of this study was to analyse current real-life burden, needs and experiences of patients who need to wear a brace for their knee, ankle and foot (KAFO). Therefor, experts were interviewed via telephone with a structured set of questions. Eight experts provided observations for patients who suffered from several diseases affecting leg muscle control. The leading patient burdens were identified as “restriction of mobility”, followed by “emotional strain” and “impaired way of walking”. Potential patient benefits were seen in “improved quality-of-life” as well as “improved way of walking” followed by a “high trust in the brace”. Experts reported a higher number of falls per year when using KAFO without the active control of a microprocessor. On a long-term basis, experts observed consequences of KAFO use as disorders of the back, reduced amount of muscles as well as swelling in areas not covered by the brace, scrub marks and degenerative impact on joints. Braces with active control of a microprocessor might result in better quality of life of patients, improved normal way of walking and perceived trust in the brace.   Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/37795/29114 How To Cite: Brüggenjürgen B., Braatz F., Greitemann B., Drewitz H., Ruetz A., Schäfer M., et al. Experts’ perceived patient burden and outcomes of knee-ankle-foot-orthoses (KAFOs) vs. microprocessor-stance-and-swing-phase-controlled-knee-ankle-foot orthoses (MP-SSCOs). Canadian Prosthetics &amp; Orthotics Journal. 2022; Volume 5, Issue 1, No.7.https://doi.org/10.33137/cpoj.v5i1.37795 Corresponding Author: Prof. Dr. med. Bernd Brüggenjürgen,Head Institute Health Services Research and Technical Orthopedics, Orthopedic Department - Medical School Hannover (MHH) at DIAKOVERE Annastift Hospital, Anna-von-Borries-Str. 1-7, 30625 Hannover, Germany. E-Mail:[email protected] ORCID ID:https://orcid.org/0000-0002-8866-080