Role of phagosomes and major histocompatibility complex class II (MHC-II) compartment in MHC-II antigen processing of Mycobacterium tuberculosis in human macrophages

Mycobacterium tuberculosis resides in phagosomes inside macrophages. In this study, we analyzed the kinetics and location of M. tuberculosis peptide-major histocompatibility complex class II (MHC-II) complexes in M. tuberculosis-infected human macrophages. M. tuberculosis peptide-MHC-II complexes were detected with polyclonal autologous M. tuberculosis-specific CD4+ T cells or F9A6 T hybridoma cells specific for M. tuberculosis antigen (Ag) 85B (96-111). Macrophages processed heat-killed M. tuberculosis more rapidly and efficiently than live M. tuberculosis. To determine where M. tuberculosis peptide-MHC-II complexes were formed intracellularly, macrophages incubated with heat-killed M. tuberculosis were homogenized, and subcellular compartments were separated on Percoll density gradients analyzed with T cells. In THP-1 cells, M. tuberculosis Ag 85B (96- 111)-DR1 complexes appeared initially in phagosomes, followed by MHC class II compartment (MIIC) and the plasma membrane fractions. In monocyte-derived macrophages, M. tuberculosis peptide-MHC-II complexes appeared only in MIIC fractions and subsequently on the plasma membrane. Although phagosomes from both cell types acquired lysosome-associated membrane protein 1 (LAMP-1) and MHC-II, THP-1 phagosomes that support formation of M. tuberculosis peptide-MHC-II complexes had increased levels of both LAMP-1 and MHC-II. Thus, M. tuberculosis phagosomes with high levels of MHC-II and LAMP-1 and MIIC both have the potential to form peptide-MHC-II complexes from M. tuberculosis antigens in human macrophages.     

A case of seminal fluid allergy successfully treated with immunotherapy in a one-day rush procedure

A 28-year-old woman was treated for seminal fluid allergy with immunotherapy using a one-day 'rush' procedure. Apart from minor anaphylactic symptoms, no serious side effects were noted during or after hyposensitization or boostering. Five weeks after the start of the hyposensitization, she was free of symptoms after unprotected coitus.     

The success of an immunization information system in the wake of Hurricane Katrina

Within days after Hurricane Katrina in September 2005, the Houston-Harris County Immunization Registry was connected to the Louisiana Immunization Network for Kids Statewide. This linkage provided immediate access to the immunization records of children who were forced to evacuate the New Orleans, Louisiana, area. One year later, >18,900 immunization records have been found, representing an estimated cost savings of more than $1.6 million for vaccine alone and $3.04 million for vaccine plus administration fees. This experience demonstrated the vital and previously unrecognized functionality of immunization information systems in a public health emergency. Here we describe the Houston-Harris County Immunization Registry's experience after Hurricane Katrina in terms of maximizing the use of immunization information systems and the implications of this experience for patients, providers, and public health for future disaster-preparedness planning.     

Chest radiographs after removal of chest drains in neonates: clinical benefit or common practice?

BACKGROUND: Chest drain insertion is a common procedure in neonatal care. Routine radiography after removal of chest drains increases radiation exposure, handling and cost, but there are few data proving clinical benefit. OBJECTIVES: To review current practice and determine the yield of routinely obtained chest radiographs (CXR). METHODS: A retrospective chart review of all infants undergoing removal of chest tubes in a single tertiary neonatal unit in New Zealand between January 1998 and July 2004 was performed. RESULTS: In total, 119 infants were identified, from the database, to have a chest drainage performed. In 19 cases, the procedure was needle aspiration or the drain was removed outside of our unit, hence these were excluded. The remaining 100 patients with 110 episodes of chest drain removal after 174 chest tube insertions were analysed. In asymptomatic infants, routine radiography showed some reaccumulation of air in nine of 35 cases of pneumothorax or of fluid in two of the five cases of pleural effusion, but chest tube reinsertion was not required. In the 12 clinically symptomatic infants, chest tubes were reinserted in five cases (four reaccumulations of pneumothorax and one pleural effusion), and one infant had symptomatic right upper lobe collapse. In the remaining infants, there were no abnormalities on CXR accounting for deterioration. CONCLUSIONS: Given the low yield for routine radiography after chest drain removal, we suggest that close observation is likely to detect clinically relevant recurrence of pneumothorax.     

Targeting self-antigens through allogeneic TCR gene transfer

Adoptive transfer of T-cell receptor (TCR) genes has been proposed as an attractive approach for immunotherapy in cases where the endogenous T-cell repertoire is insufficient. While there are promising data demonstrating the capacity of TCR-modified T cells to react to foreign antigen encounter, the feasibility of targeting tumor-associated self-antigens has not been addressed. Here we demonstrate that T-cell receptor gene transfer allows the induction of defined self-antigen-specific T-cell responses, even when the endogenous T-cell repertoire is nonreactive. Furthermore, we show that adoptive transfer of T-cell receptor genes can be used to induce strong antigen-specific T-cell responsiveness in partially MHC-mismatched hosts without detectable graft versus host disease. These results demonstrate the feasibility of using a collection of "off the shelf" T-cell receptor genes to target defined tumor-associated self-antigens and thereby form a clear incentive to test this immunotherapeutic approach in a clinical setting.     

Synthetic trimer and tetramer of 3-beta-D-ribose-(1-1)-D-ribitol-5-phosphate conjugated to protein induce antibody responses to Haemophilus influenzae type b capsular polysaccharide in mice and monkeys.

Synthetic oligosaccharides derived from the capsular polysaccharide (PRP) of Haemophilus influenzae type b were conjugated to carrier proteins via a thioether linkage. Conjugates were made of trimeric and tetrameric ribose-ribitol-phosphate and tetanus toxoid or diphtheria toxin. All conjugates elicited anti-PRP antibody responses with an increasing immunoglobulin G/immunoglobulin M ratio in adult mice and monkeys. Trimer conjugates elicited lower anti-PRP antibody responses compared with tetramer conjugates. Adult monkeys responded equally well to the tetrameric oligosaccharide-tetanus toxoid conjugate as to the oligosaccharide-CRM197 conjugate (HbOC), which elicits protective levels of serum antibodies in human infants after two or three injections.     

Chemically synthesized protein as tumour-specific vaccine: immunogenicity and efficacy of synthetic HPV16 E7 in the TC-1 mouse tumour model

Many successful candidate vaccines capable of combating tumours in animal models come to an untimely end because of the costs associated with the approval and production of the GMP-grade materials, which are usually of biological origin, for use in humans. We have used a GMP-compatible method to chemically synthesize a pure synthetic E7 protein of the human papillomavirus type 16 (HPV16-E7). This oncogen-derived protein is constitutively expressed in cervical cancer and its precursors and is thus considered as an excellent target for tumour-specific immunity. Injection of a mixture of the synthetic HPV16-E7 protein and the synthetic adjuvant CpG in mice resulted in strong functional HPV16-specific cytotoxic T-lymphocyte responses as measured by CD8+ MHC class I-tetramer staining, the detection of antigen-specific intracellular IFNgamma production and the ability to protect mice against a challenge with HPV16-E7+ TC-1 tumour cells in both prophylactic and therapeutic vaccination regimens. Our results demonstrate the potential use of pure synthetic vaccines that can be efficiently produced under GMP at low cost, which will stimulate the translation of new vaccination strategies into phase I/II clinical trials.