Molecular mechanism of complement inhibition by the trypanosome receptor ISG65

African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but becomes covalently deposited onto the surfaces of pathogens after proteolytic cleavage to C3b. Membrane-associated C3b triggers different complement-mediated effectors which promote pathogen clearance. To counter complement-mediated clearance, African trypanosomes have a cell surface receptor, ISG65, which binds to C3b and which decreases the rate of trypanosome clearance in an infection model. However, the mechanism by which ISG65 reduces C3b function has not been determined. We reveal through cryogenic electron microscopy that ISG65 has two distinct binding sites for C3b, only one of which is available in C3 and C3d. We show that ISG65 does not block the formation of C3b or the function of the C3 convertase which catalyses the surface deposition of C3b. However, we show that ISG65 forms a specific conjugate with C3b, perhaps acting as a decoy. ISG65 also occludes the binding sites for complement receptors 2 and 3, which may disrupt recruitment of immune cells, including B cells, phagocytes, and granulocytes. This suggests that ISG65 protects trypanosomes by combining multiple approaches to dampen the complement cascade.

Timing of Radiotherapy (RT) After Radical Prostatectomy (RP): Long-term outcomes in the RADICALS-RT trial [NCT00541047]

BACKGROUND

The optimal timing of radiotherapy (RT) after radical prostatectomy for prostate cancer has been uncertain. RADICALS-RT compared efficacy and safety of adjuvant RT versus an observation policy with salvage RT for PSA failure.

METHODS

RADICALS-RT was a randomised controlled trial enrolling patients with ≥1 risk factor (pT3/4, Gleason 7-10, positive margins, pre-op PSA≥10ng/ml) for recurrence after radical prostatectomy. Patients were randomised 1:1 to adjuvant RT ("Adjuvant-RT") or an observation policy with salvage RT for PSA failure ("Salvage-RT") defined as PSA≥0.1ng/ml or 3 consecutive rises. Stratification factors were Gleason score, margin status, planned RT schedule (52.5Gy/20 fractions or 66Gy/33 fractions) and treatment centre. The primary outcome measure was freedom-from-distant metastasis, designed with 80% power to detect an improvement from 90% with Salvage-RT (control) to 95% at 10yr with Adjuvant-RT. Secondary outcome measures were bPFS, freedom-from-non-protocol hormone therapy, safety and patient-reported outcomes. Standard survival analysis methods were used; HR<1 favours Adjuvant-RT.

FINDINGS

Between Oct-2007 and Dec-2016, 1396 participants from UK, Denmark, Canada and Ireland were randomised: 699 Salvage-RT, 697 Adjuvant-RT. Allocated groups were balanced with median age 65yr. 93% (649/697) Adjuvant-RT reported RT within 6m after randomisation; 39% (270/699) Salvage-RT reported RT during follow-up. Median follow-up was 7.8 years. With 80 distant metastasis events, 10yr FFDM was 93% for Adjuvant-RT and 90% for Salvage-RT: HR=0.68 (95%CI 0·43-1·07, p=0·095). Of 109 deaths, 17 were due to prostate cancer. Overall survival was not improved (HR=0.980, 95%CI 0.667-1.440, p=0.917). Adjuvant-RT reported worse urinary and faecal incontinence one year after randomisation (p=0.001); faecal incontinence remained significant after ten years (p=0.017).

INTERPRETATION

Long-term results from RADICALS-RT confirm adjuvant RT after radical prostatectomy increases the risk of urinary and bowel morbidity, but does not meaningfully improve disease control. An observation policy with salvage RT for PSA failure should be the current standard after radical prostatectomy.

Trypanosomes and complement: more than one way to die?

African trypanosomes show a remarkable ability to survive as extracellular parasites in the blood and tissue spaces of an infected mammal. Throughout the infection they are exposed to the molecules and cells of the immune system, including complement. In this opinion piece, we review decades-worth of evidence about how complement affects African trypanosomes. We highlight the discovery of a trypanosome receptor for complement C3 and we critically assess three recent studies which attempt to provide a structural and mechanistic view of how this receptor helps trypanosomes to survive in the presence of complement.

Mechanochemical tuning of a kinesin motor essential for malaria parasite transmission

Plasmodium species cause malaria and kill hundreds of thousands annually. The microtubule-based motor kinesin-8B is required for development of the flagellated Plasmodium male gamete, and its absence completely blocks parasite transmission. To understand the molecular basis of kinesin-8B's essential role, we characterised the in vitro properties of kinesin-8B motor domains from P. berghei and P. falciparum. Both motors drive ATP-dependent microtubule gliding, but also catalyse ATP-dependent microtubule depolymerisation. We determined these motors' microtubule-bound structures using cryo-electron microscopy, which showed very similar modes of microtubule interaction in which Plasmodium-distinct sequences at the microtubule-kinesin interface influence motor function. Intriguingly however, P. berghei kinesin-8B exhibits a non-canonical structural response to ATP analogue binding such that neck linker docking is not induced. Nevertheless, the neck linker region is required for motility and depolymerisation activities of these motors. These data suggest that the mechanochemistry of Plasmodium kinesin-8Bs is functionally tuned to support flagella formation.

Invariant surface glycoprotein 65 of Trypanosoma brucei is a complement C3 receptor

African trypanosomes are extracellular pathogens of mammals and are exposed to the adaptive and innate immune systems. Trypanosomes evade the adaptive immune response through antigenic variation, but little is known about how they interact with components of the innate immune response, including complement. Here we demonstrate that an invariant surface glycoprotein, ISG65, is a receptor for complement component 3 (C3). We show how ISG65 binds to the thioester domain of C3b. We also show that C3 contributes to control of trypanosomes during early infection in a mouse model and provide evidence that ISG65 is involved in reducing trypanosome susceptibility to C3-mediated clearance. Deposition of C3b on pathogen surfaces, such as trypanosomes, is a central point in activation of the complement system. In ISG65, trypanosomes have evolved a C3 receptor which diminishes the downstream effects of C3 deposition on the control of infection.

Trypanosomes evade the immune response through antigenic variation of a surface coat containing variant surface glycoproteins (VSG). They also express invariant surface glycoproteins (ISGs), which are less well understood. Here, Macleod et al. show that ISG65 of T. brucei is a receptor for complement component 3. They provide the crystal structure of T. brucei ISG65 in complex with complement C3d and show evidence that ISG65 is involved in reducing trypanosome susceptibility to C3-mediated clearance in vivo.

Inhibiting parasite proliferation using a rationally designed anti-tubulin agent

Infectious diseases caused by apicomplexan parasites remain a global public health threat. The presence of multiple ligand-binding sites in tubulin makes this protein an attractive target for anti-parasite drug discovery. However, despite remarkable successes as anti-cancer agents, the rational development of protozoan parasite-specific tubulin drugs has been hindered by a lack of structural and biochemical information on protozoan tubulins. Here, we present atomic structures for a protozoan tubulin and microtubule and delineate the architectures of apicomplexan tubulin drug-binding sites. Based on this information, we rationally designed the parasite-specific tubulin inhibitor parabulin and show that it inhibits growth of parasites while displaying no effects on human cells. Our work presents for the first time the rational design of a species-specific tubulin drug providing a framework to exploit structural differences between human and protozoa tubulin variants enabling the development of much-needed, novel parasite inhibitors.

Cryo-EM structure of a microtubule-bound parasite kinesin motor and implications for its mechanism and inhibition

Plasmodium parasites cause malaria and are responsible annually for hundreds of thousands of deaths. Kinesins are a superfamily of microtubule-dependent ATPases that play important roles in the parasite replicative machinery, which is a potential target for antiparasite drugs. Kinesin-5, a molecular motor that cross-links microtubules, is an established antimitotic target in other disease contexts, but its mechanism in Plasmodium falciparum is unclear. Here, we characterized P. falciparum kinesin-5 (PfK5) using cryo-EM to determine the motor's nucleotide-dependent microtubule-bound structure and introduced 3D classification of individual motors into our microtubule image processing pipeline to maximize our structural insights. Despite sequence divergence in PfK5, the motor exhibits classical kinesin mechanochemistry, including ATP-induced subdomain rearrangement and cover neck bundle formation, consistent with its plus-ended directed motility. We also observed that an insertion in loop5 of the PfK5 motor domain creates a different environment in the well-characterized human kinesin-5 drug-binding site. Our data reveal the possibility for selective inhibition of PfK5 and can be used to inform future exploration of Plasmodium kinesins as antiparasite targets.

High-throughput hit-squad tackles trypanosomes

African trypanosomes cause diseases of humans and their livestock. To date, a much-desired vaccine has been elusive, due in part to the immune evasion mechanisms of these cunning parasites. However, Autheman et al. have used a bold, high-throughput screen to provide hope that vaccines may be on the way.

Structure of Microtubule-Trapped Human Kinesin-5 and Its Mechanism of Inhibition Revealed Using Cryoelectron Microscopy

Kinesin-5 motors are vital mitotic spindle components, and disruption of their function perturbs cell division. We investigated the molecular mechanism of the human kinesin-5 inhibitor GSK-1, which allosterically promotes tight microtubule binding. GSK-1 inhibits monomeric human kinesin-5 ATPase and microtubule gliding activities, and promotes the motor's microtubule stabilization activity. Using cryoelectron microscopy, we determined the 3D structure of the microtubule-bound motor-GSK-1 at 3.8 Å overall resolution. The structure reveals that GSK-1 stabilizes the microtubule binding surface of the motor in an ATP-like conformation, while destabilizing regions of the motor around the empty nucleotide binding pocket. Density corresponding to GSK-1 is located between helix-α4 and helix-α6 in the motor domain at its interface with the microtubule. Using a combination of difference mapping and protein-ligand docking, we characterized the kinesin-5-GSK-1 interaction and further validated this binding site using mutagenesis. This work opens up new avenues of investigation of kinesin inhibition and spindle perturbation.

Targeting GM-CSF for collagenase-induced osteoarthritis pain and disease in mice

OBJECTIVES

Pharmacological options for treating osteoarthritis (OA) are limited and alternative treatments are required. Given the clinical data indicating that granulocyte macrophage-colony stimulating factor (GM-CSF) may be a therapeutic target in human OA, we evaluated different treatment regimens with a neutralizing anti-GM-CSF monoclonal antibody (mAb) in an experimental OA model to determine their effectiveness on amelioration of pain and disease.

METHODS

The collagenase-induced osteoarthritis (CiOA) model was induced in C57BL/6 mice, followed by different treatment regimens of anti-GM-CSF mAb or isotype control. Anti-CCL17 mAb treatment was also administered continually during the late stage of CiOA. Pain-related behavior (change in weight distribution of hind limbs), and disease (cartilage damage and osteophyte size) were assessed.

RESULTS

Blocking GM-CSF only during early synovitis in CiOA prevented pain and disease development. Once OA pain was established, regardless of the treatment regimen, anti-GM-CSF mAb treatment rapidly and efficiently ameliorated it; however, unless the treatment was continued, pain returned and disease progressed. Continual late stage blockade of GM-CSF was able to ameliorate pain (between-group difference: -6.567; 95% confidence interval (CI): -10.12, -3.011) and suppress cartilage damage (P = 0.0317, 95% CI: -1.75, -0.0556). Continual late stage blockade of CCL17 showed similar effects on pain and disease development.

CONCLUSIONS

Early and short-term GM-CSF neutralization is effective at preventing CiOA pain and disease development but, once pain is evident, continual GM-CSF blockade is required to prevent pain from returning and to suppress disease progression in mice. These data reinforce the potential benefits of anti-GM-CSF (and anti-CCL17) mAb therapy in OA and should inform further clinical trials.

Structural determinants of microtubule minus end preference in CAMSAP CKK domains

CAMSAP/Patronins regulate microtubule minus-end dynamics. Their end specificity is mediated by their CKK domains, which we proposed recognise specific tubulin conformations found at minus ends. To critically test this idea, we compared the human CAMSAP1 CKK domain (HsCKK) with a CKK domain from Naegleria gruberi (NgCKK), which lacks minus-end specificity. Here we report near-atomic cryo-electron microscopy structures of HsCKK- and NgCKK-microtubule complexes, which show that these CKK domains share the same protein fold, bind at the intradimer interprotofilament tubulin junction, but exhibit different footprints on microtubules. NMR experiments show that both HsCKK and NgCKK are remarkably rigid. However, whereas NgCKK binding does not alter the microtubule architecture, HsCKK remodels its microtubule interaction site and changes the underlying polymer structure because the tubulin lattice conformation is not optimal for its binding. Thus, in contrast to many MAPs, the HsCKK domain can differentiate subtly specific tubulin conformations to enable microtubule minus-end recognition.

Pulseless electrical activity following traumatic cardiac arrest: Sign of life or death?

BACKGROUND

Generally considered a sign of life, PEA is the most common arrhythmia encountered following pre-hospital traumatic cardiac arrest. Some recommend cardiac ultrasound (CUS) to determine cardiac wall motion (CWM) prior to terminating resuscitation efforts. This purpose of this study was to evaluate the outcomes of patients with traumatic cardiac arrest presenting with PEA, with and without CWM.

METHODS

Trauma patients who underwent pre-hospital CPR were identified from the registries of two level-1 trauma centers. Pre-hospital management by emergency medical transport services was guided by advanced life support protocols. The on-duty trauma surgeon directed the resuscitations and performed or supervised CUS and determined CWM.

RESULTS

Among 277 patients who underwent pre-hospital CPR, 110 patients had PEA on arrival to ED. 69 (62.7%) were injured by blunt mechanisms. Median CPR duration was 20.0 and 8.0 min for pre-hospital and ED, respectively. Sixty-three patients (22.7%) underwent resuscitative thoracotomy. One hundred seventy-two patients (62.1%) received CUS and of these 32 (18.6%) had CWM. CWM was significantly associated with survival to hospital admission (21.9% vs. 1.4%; P < 0.001); however, no patient with CUS survived to hospital discharge. Overall, only one patient with PEA on arrival survived to discharge.

CONCLUSION

Following pre-hospital traumatic cardiac arrest, PEA on arrival portends death. Although CWM is associated with survival to admission, it is not associated with meaningful survival. Heroic resuscitative measures may be unwarranted for PEA following pre-hospital traumatic arrest, regardless of CWM.

Enhancement of T cell responses as a result of synergy between lower doses of radiation and T cell stimulation

As a side effect of cancer radiotherapy, immune cells receive varying doses of radiation. Whereas high doses of radiation (>10 Gy) can lead to lymphopenia, lower radiation doses (2-4 Gy) represent a valid treatment option in some hematological cancers, triggering clinically relevant immunological changes. Based on our earlier observations, we hypothesized that lower radiation doses have a direct positive effect on T cells. In this study, we show that 0.6-2.4 Gy radiation enhances proliferation and IFN-γ production of PBMC or purified T cells induced by stimulation via the TCR. Radiation with 1.2 Gy also lowered T cell activation threshold and broadened the Th1 cytokine profile. Although radiation alone did not activate T cells, when followed by TCR stimulation, ERK1/2 and Akt phosphorylation increased above that induced by stimulation alone. These changes were followed by an early increase in glucose uptake. Naive (CD45RA(+)) or memory (CD45RA(-)) T cell responses to stimulation were boosted at similar rates by radiation. Whereas increased Ag-specific cytotoxic activity of a CD8(+) T cell line manifested in a 4-h assay (10-20% increase), highly significant (5- to 10-fold) differences in cytokine production were detected in 6-d Ag-stimulation assays of PBMC, probably as a net outcome of death of nonstimulated and enhanced response of Ag-stimulated T cells. T cells from patients receiving pelvic radiation (2.2-2.75 Gy) also displayed increased cytokine production when stimulated in vitro. We report in this study enhanced T cell function induced by synergistic radiation treatment, with potential physiological significance in a wide range of T cell responses.

Identification of epistasis through a partial advanced intercross reveals three arthritis loci within the Cia5 QTL in mice

Identification of genes controlling complex diseases has proven to be difficult; however, animal models may pave the way to determine how low penetrant genes interact to promote disease development. We have dissected the Cia5/Eae3 susceptibility locus on mouse chromosome 3 previously identified to control disease in experimental models of multiple sclerosis and rheumatoid arthritis. Congenic strains showed significant but small effects on severity of both diseases. To improve the penetrance, we have now used a new strategy that defines the genetic interactions. The QTL interacted with another locus on chromosome 15 and a partial advanced intercross breeding of the two congenic strains for eight generations accumulated enough statistical power to identify interactions with several loci on chromosome 15. Thereby, three separate loci within the original QTL could be identified; Cia5 affected the onset of arthritis by an additive interaction with Cia31 on chromosome 15, whereas the Cia21 and Cia22 affected severity during the chronic phase of the disease through an epistatic interaction with Cia32 on chromosome 15. The definition of genetic interactions was a prerequisite to dissect the Cia5 QTL and we suggest the partial advanced intercross strategy to be helpful also for dissecting other QTL controlling complex phenotypes.

Chest Radiographs of Limited Utility in the Diagnosis of Blunt Traumatic Aortic Laceration

BACKGROUND

The radiographic diagnosis of blunt traumatic aortic laceration (BTAL) remains problematic. We reviewed our experience with chest radiographic signs of BTAL at a single trauma center.

METHODS

The chest radiographs of 188 consecutive blunt trauma patients with suspected BTAL who underwent portable chest radiography and aortography were retrospectively reviewed by a thoracic radiologist. The presence or absence of 15 radiographic findings were recorded, and the sensitivity and specificity of individual radiographic signs and combinations of signs were determined.

RESULTS

There were 10 patients with BTAL. Although three signs showed greater than 90% sensitivity for BTAL, these signs showed low specificity, and no significant improvement in overall accuracy was achieved by combining radiographic findings.

CONCLUSION

The experience at our institution suggests that chest radiographs have limited utility in the accurate diagnosis of blunt traumatic aortic laceration. Cross-sectional imaging techniques will likely become the preferred imaging procedures for evaluating patients with suspected BTAL.

Blockade of collagen-induced arthritis post-onset by antibody to granulocyte-macrophage colony-stimulating factor (GM-CSF): requirement for GM-CSF in the effector phase of disease

There is mounting evidence for a role of the growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF) in inflammatory disease, including arthritis. In the present study, we examined the effectiveness of treatment of collagen-induced arthritis (CIA) with a neutralizing mAb to GM-CSF. DBA/1 mice were immunized for the development of CIA and treated at different times, and with different doses, with neutralizing mAb to GM-CSF or isotype control mAb. Anti-GM-CSF mAb treatment prior to the onset of arthritis, at the time of antigen challenge, was effective at ameliorating the ensuing disease. Modulation of arthritis was seen predominantly as a reduction in overall disease severity, both in terms of the number of limbs affected per mouse and the clinical score of affected limbs. Importantly, anti-GM-CSF mAb treatment ameliorated existing disease, seen both as a reduction in the number of initially affected limbs progressing and lower numbers of additional limbs becoming affected. By histology, both inflammation and cartilage destruction were reduced in anti-GM-CSF-treated mice, and the levels of tumor necrosis factor-a and IL-1beta were also reduced in joint tissue washouts of these mice. Neither humoral nor cellular immunity to type II collagen, however, was affected by anti-GM-CSF mAb treatment. These results suggest that the major effect of GM-CSF in CIA is on mediating the effector phase of the inflammatory reaction to type II collagen. The results also highlight the essential role of GM-CSF in the ongoing development of inflammation and arthritis in CIA, with possible therapeutic implications for rheumatoid arthritis.

Antibodies to type II collagen and HLA disease susceptibility markers in rheumatoid arthritis

OBJECTIVE

To seek associations between antibodies to native and denatured type II collagen (NCII and DCII) and HLA in rheumatoid arthritis (RA).

METHODS

One hundred fourteen patients with clinically well-defined RA were HLA-DR and DQ typed. Those who were DR4 positive were subtyped for DRB1*0401-*0408 alleles by polymerase chain reaction using allele-specific oligonucleotide probes. Antibodies to human NCII and DCII (heat-denatured) were measured by enzyme-linked immunosorbent assay. The frequency of HLA alleles was compared in patients grouped according to the presence and absence of antibodies to NCII and DCII.

RESULTS

Twenty-seven patients (24%) were positive for antibodies to NCII. There was a significant increase in the frequency of HLA-DR7 in anti-NCII-positive patients compared with anti-NCII-negative patients (30% versus 9%; P = 0.019) and a significant decrease in HLA-DR3 (7% versus 28%; P = 0.044). Repeating the analyses after excluding the 16 patients who were DR7 positive revealed a significant increase in the frequency of HLA-DR1 in anti-NCII-positive patients compared with anti-NCII-negative patients (63% versus 27%; P = 0.045). Moreover, antibodies to NCII were associated with the third hypervariability region susceptibility sequence QRRAA that is present in DRB1*0101, *0404, *0405, and *0408 (84% versus 47%; P = 0.0085); 24 of 27 anti-NCII-positive patients were positive for either DR7, DR1, or DRB1*0404 or *0408. Thirty patients (26%) were positive for antibodies to DCII. There was a significant increase in the frequency of HLA-DR3 in anti-DCII-positive patients compared with anti-DCII-negative patients (40% versus 18%; P = 0.028).

CONCLUSION

The genetic associations between HLA-DR alleles and antibodies to CII in RA patients is in keeping with the collagen-induced arthritis model and implicates autoimmunity to CII as a major component in the multifactorial pathogenesis of RA.

Psychiatric treatment of children and adolescents in rural communities. Myths and realities

Rural child and adolescent psychiatry offers many challenges, a varied and interesting practice, and the satisfaction of performing needed and important work in an environment in which one's presence is valued. The successful psychiatrist can expect to be an integrated and appreciated member of the community. The fit is not a good one for every practitioner, however. Not only are incomes lower, although the cost of living is low as well, but practitioners may find they have only exchanged urban stresses for rural pressures. The characteristics important for the child and adolescent psychiatrist are the same for rural and urban settings: flexibility, creativity and innovation, competence, self confidence, a good sense of boundaries, a good balance between personal and private life, supportive personal relationships, and a sense of humor. One must be a child advocate, have a willingness to give of one's self and one's time, and be down to earth, comfortable with oneself, and capable of self entertainment. Training programs with access to rural populations can introduce residents to rural child and adolescent psychiatry while supporting those who are already in practice. The authors hope that this article will promote a dialogue with psychiatrists considering relocation to a rural area and encourage training programs to prepare residents for rural practice.

Mimotopes identified by phage display for the monoclonal antibody CII-C1 to type II collagen

The characterization of B cell epitopes has been advanced by the use of random peptide libraries displayed within the coat protein of bacteriophage. This technique was applied to the monoclonal antibody (mAb) C1 to type II collagen (CII-C1). CII-C1 is known to react with a conformational epitope on type II collagen that includes residues 359-363. Three rounds of selection were used to screen two random nonameric phage libraries and 18 phagotopes were isolated. CII-C1 reacted by ELISA with 17 of the 18 phagotopes: one phagotope contained a stop codon. Of the eight most reactive phage, seven inhibited the reactivity by ELISA of CII-C1 with type II collagen. Of the 18 phage isolated, 11 encoded the motif F-G-x-Q with the sequence F-G-S-Q in 6, 2 encoded F-G-Q, and one the reverse motif Q-x-y-F. Most phagotopes that inhibited the reactivity of CII-C1 encoded two particular motifs consisting of two basic amino acid residues and a hydrophobic residue in the first part of the insert and the F-G-x-Q or F-G-Q motif in the second part; phagotopes which contained only one basic residue in the first part of the sequence were less reactive. These motifs are not represented in the linear sequence of type II collagen and thus represent mimotopes of the epitope for CII-C1 on type II collagen. There were five phagotopes with peptide inserts containing the sequence RLPFG occurring in the Epstein-Barr virus nuclear antigen, EBNA-1. This is of interest because EBV has been implicated in the initiation of rheumatoid arthritis (RA) by reason of increased reactivity to EBNA-1 in RA sera. In conclusion, the phage display technique disclosed mimotopes for a conformational epitope of type II collagen, and revealed an interesting homology with a sequence of the EBNA-1 antigen from Epstein Barr virus.

IgG subclasses of antibodies to type II collagen in rheumatoid arthritis differ from those in systemic lupus erythematosus and other connective tissue diseases

OBJECTIVE

To compare IgG subclass distribution of autoantibodies to native type II collagen in patients with rheumatoid arthritis (RA) and in other rheumatic and inflammatory diseases including systemic lupus erythematosus (SLE).

METHODS

The IgG subclass of antibodies to native type II collagen were measured by modified ELISA using chemiluminescent detection and subclass-specific monoclonal antibodies in sera that contained IgG antibodies to collagen using conventional ELISA.

RESULTS

Antibodies to native type II collagen were present in sera of 20% of 323 patients with RA. 9% of 211 patients with SLE, 12% of 50 patients with osteoarthritis, and 13% of 75 patients with other chronic inflammatory diseases, but the highest levels occurred in patients with RA. The IgG subclass distribution of these antibodies differed markedly according to disease. In RA the predominant subclasses were IgG1 (58%) and IgG3 (47%), whereas in SLE the predominant subclass was IgG4 (69%). IgG2 was represented across all disease groups. Overall the frequency of IgG1 and/or IgG3 antibodies to type II collagen (84%) was significantly greater in RA than in other disease groups combined (20%) (p < 0.0001).

CONCLUSION

Antibodies to native collagen in RA were predominantly of the complement fixing and potentially damaging subclasses IgG1 and IgG3, but in SLE were of the non-complement fixing subclass IgG4; in other diseases, where present, antibodies were mostly IgG2 and of low level. These observations support the importance of autoimmunity to collagen in the pathogenesis of RA.

Colorimetric analysis of surface reactive amino groups on poly(lactic acid-co-lysine):poly(lactic acid) blends

The quantification of functional amino (NH2) groups on poly(lactic acid-co-lysine):(poly(L-lactic acid (PLAL:PLA) blends was performed using a colorimetric assay based on the reaction of sulpho-succinimidyl-4-O-(4,4'-dimethoxytrityl)-butyrate (sulpho-SDTB) with primary amino groups. The colorimetric assay was used to assess the available reactive sites for coupling of biologically active species to PLAL. Blends were created that contained from 10 to 70 wt% poly(lactic acid-co-lysine). Bulk lysine contents within the blends were determined by amino acid analysis and ranged from 9.1 micromol g(-1) to 52.9 micromol g(-1) for blends created using PLA of 100000g mol(-1) molecular weight. Surface amino group concentrations on the same set of blends ranged from 0.23 to 1.45 nmol cm(-2). Similar surface amino groups concentrations were measured on blends using 50000, 200000 and 300000g mol(-1) poly(lactic acid). Non-specific interactions of the colorimetric assay reagents with the PLAL-containing blends were measured on blends prepared from epsilon-amino protected PLAL and 100000g mol(-1) PLA. The presence of amino groups within the top 50 angstroms was confirmed by X-ray photoelectron spectroscopy.

Characterization and development of RGD-peptide-modified poly(lactic acid-co-lysine) as an interactive, resorbable biomaterial

The design of biomaterials containing specific ligands on the surface offers the possibility of creating materials that can interact with and potentially control mammalian cell behavior. Biodegradable materials further provide the significant advantage that the polymer will disappear in vivo, obviating long-term negative tissue responses as well as the need for retrieval. In earlier studies we synthesized and characterized arginine-glycine-aspartic acid (RGD) peptide-modified poly(lactic acid-co-lysine) (PLAL). In this study, both bulk properties and surface features have been characterized, with a focus on surface analysis as a means of interpreting observed changes in cell behavior. Bulk peptide attachments were performed using 1,1'-carbonyldiimidazole (CDI). Amino groups were measured using colorimetric assays and X-ray photoelectron spectroscopy (XPS). Peptides were measured by incorporating iodine into the peptide as a distinct elemental marker for use with XPS. Typical samples contained 13 +/- 4 pmol/cm2 of amino groups and 4 +/- 0.2 pmol/ cm2 of peptides, as calculated from XPS measurements of nitrogen and iodine. The wettability and crystallinity of the samples were determined by contact angles and differential scanning calorimetry, respectively. Wettability and crystallinity were not altered by the incorporation of lysine or peptides. After incubating bovine aortic endothelial (BAE) cells for 4 h on surfaces with RGD-containing peptides, the mean spread cell area increased from 77 +/- 2 microns2 to 405 +/- 29 microns2 compared to 116 +/- 11 microns2 on poly(lactic acid), 87 +/- 4 microns2 on PLAL, and 105 +/- 4 microns2 on surfaces with RDG-containing (control) peptides. The significance of this work is that the first synthetic interactive, resorbable biomaterial has been developed, and use of this material to control cell behavior has been demonstrated.

Measurement of exposure to mouse urinary proteins in an epidemiological study

OBJECTIVES

To develop an assay to measure airborne mouse urinary protein (MUP) and to assess the occupational exposure to MUP in the workforce of three establishments as part of an epidemiological study examining the influence of aeroallergen exposure on the development of allergic respiratory disease.

METHODS

Personal air samples were collected from nine exposure groups during a workshift. A sensitive and reproducible competitive inhibition assay, which used rabbit antisera specific for MUP, was developed and used to measure the occupational exposure to MUP.

RESULTS

The personal measurements of MUP showed that people with direct contact with mice (animal technicians) had the highest exposure followed in decreasing order by those working with anaesthetised animals or their tissue (postmortem workers and scientists) and those with indirect contact with mice (supervisors, office workers, and slide production workers). The only difference in concentrations of MUP between the three establishments were found for cage cleaners, which reflected differences in working practises for this exposure category. Air samples collected during the performance of specific tasks showed that high exposures to MUP were associated with handling mice, indirect contact with mice, and washing floors.

CONCLUSIONS

Exposure to mouse urinary proteins has been measured in the occupational environment. This information can be used to determine the relation between exposure to MUP and the development of allergic and respiratory disease.

Antibodies to type II collagen in early rheumatoid arthritis. Correlation with disease progression

OBJECTIVE

To establish that frequencies and levels of IgG antibodies to type II collagen are higher in early rheumatoid arthritis (RA), and to correlate these results with disease activity.

METHODS

Forty-four patients were characterized as having early RA. Patient sera obtained at initial presentation and at 12 months were tested by enzyme-linked immunosorbent assay for IgG antibodies to native and denatured type II collagen.

RESULTS

IgG antibodies to native and denatured type II collagen were detected at initial presentation in 27% and 82% of patients, respectively, and after 12 months in 14% and 50%, respectively. The presence of antibodies to native collagen was associated with activity of RA and severity of symptoms, and loss of antibodies at 12 months was associated with initially erosive RA and the DRB1 disease susceptibility motif.

CONCLUSION

Levels of serum IgG antibodies to collagen in RA decrease over time and, therefore, are not attributable simply to cartilage destruction. The presence of early positivity for these antibodies, together with the RA susceptibility motif, appears to be predictive of rapidly progressive RA.

A major outbreak of asthma associated with a thunderstorm: experience of accident and emergency departments and patients' characteristics. Thames Regions Accident and Emergency Trainees Association

OBJECTIVE

To investigate the time course of an epidemic of asthma after a thunderstorm, characteristics of patients affected, and the demand on emergency medical resources.

DESIGN

Study of registers and records in accident and emergency departments and questionnaire to staff.

SETTING

London area.

SUBJECTS

All patients presenting at 12 accident and emergency departments with asthma or other airway disease.

MAIN OUTCOME MEASURES

Numbers of patients, clinical features, information on shortage of resources--equipment, drugs and staff.

RESULTS

The epidemic had a sudden onset on 24 June 1994; 640 patients with asthma or other airways disease attended during 30 hours from 1800 on 24 June, nearly 10 times the expected number. Over half (365) the patients were aged 21 to 40 years. A history of hay fever was recorded in 403 patients; for 283 patients this was the first known attack of asthma; a history of chronic obstructive airways disease was recorded in 12 patients. In all, 104 patients were admitted (including five to an intensive care unit). Several departments ran out of equipment or drugs, called in additional doctors, or both.

CONCLUSIONS

This study supports the view that this epidemic was larger than previously reported epidemics and the hypothesis that "thunderstorm associated asthma' is related to aeroallergens. Demands on resources were considerable; a larger proportion of patients needing intensive care would have caused greater problems.

Comparative epitope mapping of antibodies to collagen in women with silicone breast implants, systemic lupus erythematosus and rheumatoid arthritis

Previous work has shown that women with silicone gel breast implants have an increased frequency of autoantibodies to collagen types I and II. 70 women without a specific autoimmune disease, using criteria of the American College of Rheumatology, but who had silicone breast implants were studied for the presence of serum antibodies to native and denatured human types I and II collagen by ELISA. 82 women with systemic lupus erythematosus (SLE), 94 women with rheumatoid arthritis (RA), and 133 healthy controls were also studied. There was a high frequency of autoantibodies to collagen in each of the groups when compared to the healthy controls. The specificities of these antibodies were found to differ markedly when examined by immunoblotting using peptides derived by cyanogen bromide digestion of the collagens. Sera from women with silicone implants reacted with multiple peptides of type I collagen in an individual-specific manner, but sera from women with SLE or RA reacted weakly with a restricted range of peptides. Against type II collagen, sera from women with RA reacted strongly with multiple peptides, while sera from women with silicone implants or SLE reacted only weakly or not at all. The patterns of reactivity against collagens by sera from women with silicone implants suggest that silicone can act as an adjuvant to enhance the immunogenicity of type I collagen.

Antibodies to collagen: comparative epitope mapping in women with silicone breast implants, systemic lupus erythematosus and rheumatoid arthritis

Women with silicone breast implants have a significantly increased frequency of antibodies to collagen types I and II. To characterize the specificity of these antibodies, 70 women without a specific autoimmune disease, according to the criteria of the American College of Rheumatology, but who had silicone breast implants were studied for the presence of serum antibodies to native and denatured human types I and II collagen by ELISA. Positive sera were further studied by immunoblotting using peptides derived by cyanogen bromide digestion of the collagens. Samples of 82 women with systemic lupus erythematosus (SLE), 94 women with rheumatoid arthritis (RA), and 133 healthy controls were studied concurrently. There was a high frequency of autoantibodies to collagen in each of the study groups when compared to the healthy controls. However, and of particular interest, the epitope specificity of the autoantibodies differed markedly. Sera from women with silicone implants reacted strongly in an individual-specific manner with multiple peptides of type I collagen, whereas sera from women with SLE and RA reacted only weekly with a restricted range of peptides of type I collagen. Sera from women with RA reacted strongly with multiple peptides of type II, whereas sera from women with silicone implants or SLE reacted only weakly. The reactivity of women with silicone implants suggests that silicone or its biodegradation products can act as adjuvants in situ to enhance the immunogenicity of type I collagen, or protein-silicone conjugates.

Specificity of antibodies to type II collagen in early rheumatoid arthritis

OBJECTIVE

To analyze the antibody response to native type II collagen in early rheumatoid arthritis (RA), examining the immunoglobulin isotypes, and polypeptide epitopes recognized, in patients followed over a 2-year period from within 6 months of the first occurrence of symptoms.

METHODS

Sera from 16 patients were studied, of whom 10 had antibodies to native type II collagen and 6 did not. The clinical and laboratory assessment, carried out initially and at 6 monthly intervals included the number of 1958 ARA criteria fulfilled, Ritchie index, erythrocyte sedimentation rate, rheumatoid factor and radiological assessment. An ELISA was used to measure IgG, IgA and IgM antibodies, and immunoblotting to identify the number and location of epitopes, using polypeptides prepared by cyanogen bromide digestion of human type II collagen.

RESULTS

Antibodies to type II collagen were present in all sequential serum samples for the 10 antibody positive patients. None of the 6 patients who initially lacked antibodies developed them. The antibodies were of IgG isotype in 9, of IgA isotype in 8, and of IgM isotype exclusively in one. At the initial clinical assessment patients with antibodies to collagen were indistinguishable from those without. At 12 and 24 months patients with antibodies fulfilled significantly more ARA criteria than antibody negative patients. The patterns of antibody reactivity to collagen polypeptides by immunoblotting were constant over time but differed from patient to patient.

CONCLUSION

The presence of an established and persisting IgG antibody response to type II collagen in early RA before cartilage destruction is evident points to a subset of RA, perhaps equivalent to the collagen induced model in animals, in which this immune response is intrinsic to pathogenesis.

Antibodies to the collagen-like region of C1q and type II collagen are independent non-cross-reactive populations in systemic lupus erythematosus and rheumatoid arthritis

The collagen-like region (CLR) of the first component of complement, C1q, and type II collagen are structurally similar, raising the possibility of epitopes in common, and of the existence of autoantibodies that are cross-reactive. Accordingly, antibodies to the CLR of C1q and to type II collagen were measured in patients' sera with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) by an ELISA. IgG antibodies to the CLR of C1q were present in 17% of patients with SLE but none with RA, and IgA antibodies were present in 10% and 8% of patients with SLE and RA, respectively. IgG antibodies to type II collagen were present in 15% and 25% of patients with SLE and RA, respectively, and IgA antibodies in 15% and 28% of patients with SLE and RA, respectively. There was no correlation in either disease between the serum levels of antibodies to the CLR of C1q and antibodies to type II collagen. For sera with antibodies to both antigens, neither competitive inhibition by ELISA nor preabsorption with the alternative antigen affected the level of reactivity to the other antigen. Thus antibodies to the CLR of C1q and antibodies to type II collagen are independent and non-cross-reactive populations, and presumably occur by different types of immunogenic stimulation.

Bacterial adhesion to protein-coated hydrogels

Extended wear soft contact lenses have been implicated in the increased occurrence of corneal bacterial infections. This research investigated the effects of polymer chemistry, water content, and pre-sorbed proteins upon the adherence of Pseudomonas aeruginosa to model hydrogels with chemistries similar to those of extended wear soft contact lenses. The hydrogels were exposed to washed suspensions of P. aeruginosa in a laminar flow cell. Albumin, fibrinogen, desialylated fibrinogen, or mucin were deposited on the hydrogels before exposure to the bacteria. Results showed that with or without protein pre-exposure, bacterial adhesion decreased as water content increased. In the presence of the sorbed protein, the number of adherent bacteria increased by about 45%, and all four proteins caused similar increases in adhesion. Bacterial adhesion was not significantly influenced by the presence of sialic acid residues in the pre-sorbed protein.

Bacterial adhesion to poly(HEMA)-based hydrogels

The effects of water content and comonomer chemistry upon the adhesion of Pseudomonas aeruginosa to poly(hydroxyethyl methacrylate)-based hydrogels were studied. Hydrogels which varied in swollen water content from 33-69 wt% were polymerized onto glass microscope slides pretreated with a vinyl silane. The hydrogel water content was varied by adding methacrylic acid (1-5 wt%) or N-vinyl pyrrolidone (NVP, 10-25 wt%) or combinations of the two comonomers. The resulting hydrogel surfaces, which were 0.1 mm thick, transparent, and adherent to the glass slide, formed the test surfaces of laminar flow cells (Re = 1.3, wall shear rate = 1.6/s). The bacteria were grown for 8 h in tryptic soy broth (TSB), washed by filtration, and collected on 0.45-microns filters, resuspended in phosphate buffered saline (PBS) at pH = 7.2, and recirculated through the flow cell and across the test surface at 0.85 mL/min for 2 h. Results show that P. aeruginosa adhered less to hydrogels with higher water contents. In the presence of TSB and possible poly(NVP) contamination, the concentration of adherent bacteria was reduced to low and uniform levels independent of the hydrogel chemistry.

Subclasses of immunoglobulins and autoantibodies in autoimmune diseases

The differing capacity of subclasses of IgG to bind to protein A and protein G was used in a sequential affinity purification procedure to examine immunoglobulin isotypes and subclasses in autoimmune disease. The utility of the procedure is that affinity-purified fractions containing particular isotypes and subclasses of immunoglobulin can be analyzed for their content of autoantibodies using standard techniques. For each of four autoimmune diseases studied, chronic active hepatitis, Sjogren's syndrome, primary biliary cirrhosis, and rheumatoid arthritis, there were characteristic protein elution profiles and the various disease-specific autoantibodies showed preferential distributions among the isotypes and subclasses. Moreover there was not an absolute correlation between an increased level of a particular subclass and the occurrence of antibodies of that subclass. The occurrence of highly disease-specific immunoglobulin subclass profiles suggests that the hypergammaglobulinemia associated with autoimmunity cannot be attributed entirely to polyclonal B-cell activation. Rather, there are disease-specific alterations in isotype subclass switching which may reflect different cytokine-dependent influences on autoimmune B cells and their products.

Distinction between 'inflammatory' and 'immune' macrophages killing Listeria monocytogenes in murine infection

Two populations of efficiently phagocytic and bacteriolytic cells have been defined in the peritoneal cavity following infection of mice with Listeria monocytogenes. One was the result of a transient inflammatory response 2 days after intraperitoneal (i.p.) infection. It consisted of a mixture of monocyte/macrophages and neurotrophils which, when separated on Percoll gradients or by adherence, were both highly bacteriolytic compared with normal resident peritoneal macrophages. It was rich in recently divided cells as evidenced by in vivo labelling with tritiated thymidine. Although having the enlarged, vacuolated appearance of 'activated' macrophages, three-quarters of the monocyte/macrophages stained positive for myeloperoxidase (MPO), characteristic of monocytes rather than mature macrophages. In contrast, intravenous (i.v.) infection, which localizes in spleen and liver, did not produce this early response in the peritoneal cavity. However, 8 days after either i.v. or i.p. infection there existed in the peritoneal cavity a highly active population of cells comprising chiefly macrophages of typical foamy appearance which did not stain for MPO+. They were actively phagocytic and bacteriolytic and, like the early inflammatory exudate, produced increased amounts of oxygen degradative products. They appear to typify the concept of macrophages activated by T cell mediated immunity. Two day peritoneal exudates induced in these previously infected mice by i.p. rechallenge with L. monocytogenes organisms comprised mostly MPO- macrophages.

Vanillyl mandelic acid excretion in unilateral electroconvulsive therapy (ECT)

The twenty-four hour urinary excretion of vanillyl mandelic acid was determined in a group of eleven psychiatric patients prior to and during the day of the fifth unilateral electroconvulsive treatment. The patients were all determined by their treating psychiatrists and by psychological testing to be psychotically depressed. In ten of the eleven patients a marked decrease in excreted vanillyl mandelic acid was apparent from the pretreatment level to the fifth treatment level. In one of the eleven patients there was a slight rise from the pretreatment level to the excreted level during the fifth day of treatment. The mean pretreatment determination of vanillyl mandelic acid was 4.2 mg per twenty-four hours; the mean determination made on the fifth treatment was 2.8 mg per twenty-four hours.