Format chain exchange (FORCE) for high-throughput generation of bispecific antibodies in combinatorial binder-format matrices

Generation of bispecific antibodies (bsAbs) requires a combination of compatible binders in formats that support desired functionalities. Here, we report that bsAb-matrices can be generated by Format Chain Exchange (FORCE), enabling screening of combinatorial binder/format spaces. Input molecules for generation of bi/multi-valent bsAbs are monospecific entities similar to knob-into-hole half-antibodies, yet with complementary CH3-interface-modulated and affinity-tagged dummy-chains. These contain mutations that lead to limited interface repulsions without compromising expression or biophysical properties of educts. Mild reduction of combinations of educts triggers spontaneous chain-exchange reactions driven by partially flawed CH3-educt interfaces resolving to perfect complementarity. This generates large bsAb matrices harboring different binders in multiple formats. Benign biophysical properties and good expression yields of educts, combined with simplicity of purification enables process automation. Examples that demonstrate the relevance of screening binder/format combinations are provided as a matrix of bsAbs that simultaneously bind Her1/Her2 and DR5 without encountering binder or format-inflicted interferences.

Bispecific antibodies have been generated in many different formats and it is becoming clear that rational design alone cannot create optimal functionalities. Here the authors introduce the high throughput methodology, Format Chain Exchange (FORCE), to enable combinatorial generation of bispecific antibodies.

Childhood allergy is preceded by an absence of gut lactobacilli species and higher levels of atopy-related plasma chemokines

Alterations in the composition and reduced diversity of the infant microbiome are associated with allergic disease in children. Further, an altered microbiota is linked to immune dysregulation, including skewing of different T helper (Th) subsets, which is also seen in atopic individuals. The aim of this study was, therefore, to investigate the associations between gut lactobacilli and Th‐related plasma factors in allergy development during childhood. A total of 194 children with known allergy status at 1 year of age were followed to 10 years of age. We used real‐time polymerase chain reaction (PCR) to investigate the presence of three lactobacilli species (Lactobacillus casei, L. paracasei, L. rhamnosus) in infant fecal samples (collected between 1 week and 2 months of age) from a subgroup of children. Plasma chemokines and cytokines were quantified at 6 months and at 1, 2, 5 and 10 years of age with Luminex or enzyme‐linked immunosorbent assay (ELISA). Fractional exhaled nitrogen oxide (FeNO) was measured and spirometry performed at 10 years of age. The data were analysed by non‐parametric testing and a logistic regression model adjusted for parental allergy. An absence of these lactobacilli and higher levels of the chemokines BCA‐1/CXCL13, CCL17/TARC, MIP‐3α/CCL20 and MDC/CCL22 in plasma at 6 months of age preceded allergy development. The presence of lactobacilli associated with lower levels of atopy‐related chemokines during infancy, together with higher levels of interferon (IFN)‐γ and lower FeNO during later childhood. The results indicate that the presence of certain lactobacilli species in the infant gut may influence allergy‐related parameters in the peripheral immune system, and thereby contribute to allergy protection.

A Non-interventional Clinical Trial Assessing Immune Responses After Radiofrequency Ablation of Liver Metastases From Colorectal Cancer

Background: Radiofrequency ablation (RFA) is an established treatment option for malignancies located in the liver. RFA-induced irreversible coagulation necrosis leads to the release of danger signals and cellular content. Hence, RFA may constitute an endogenous in situ tumor vaccination, stimulating innate and adaptive immune responses, including tumor-antigen specific T cells. This may explain a phenomenon termed abscopal effect, namely tumor regression in untreated lesions evidenced after distant thermal ablation or irradiation. In this study, we therefore assessed systemic and local immune responses in individual patients treated with RFA.

Methods: For this prospective clinical trial, patients with liver metastasis from colorectal carcinoma (mCRC) receiving RFA and undergoing metachronous liver surgery for another lesion were recruited (n = 9) during a 5-year period. Tumor and non-malignant liver tissue samples from six patients were investigated by whole transcriptome sequencing and tandem-mass spectrometry, characterizing naturally presented HLA ligands. Tumor antigen-derived HLA-restricted peptides were selected by different predefined approaches. Further, candidate HLA ligands were manually curated. Peripheral blood mononuclear cells were stimulated in vitro with epitope candidate peptides, and functional T cell responses were assessed by intracellular cytokine staining. Immunohistochemical markers were additionally investigated in surgically resected mCRC from patients treated with (n = 9) or without RFA (n = 7).

Results: In all six investigated patients, either induced immune responses and/or pre-existing T cell immunity against the selected targets were observed. Multi-cytokine responses were inter alia directed against known tumor antigens such as cyclin D1 but also against a (predicted) mutation contained in ERBB3. Immunohistochemistry did not show a relevant influx of immune cells into distant malignant lesions after RFA treatment (n = 9) as compared to the surgery only mCRC group (n = 7).

Conclusions: Using an individualized approach for target selection, RFA induced and/or boosted T cell responses specific for individual tumor antigens were more frequently detectable as compared to previously published observations with well-characterized tumor antigens. However, the witnessed modest RFA-induced immunological effects alone may not be sufficient for the rejection of established tumors. Therefore, these findings warrant further clinical investigation including the assessment of RFA combination therapies e.g., with immune stimulatory agents, cancer vaccination, and/or immune checkpoint inhibitors.

Epstein-Barr Virus, but Not Cytomegalovirus, Latency Accelerates the Decay of Childhood Measles and Rubella Vaccine Responses-A 10-Year Follow-up of a Swedish Birth Cohort

BACKGROUND

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are ubiquitous and persistent herpesviruses commonly acquired during childhood. Both viruses have a significant impact on the immune system, especially through mediating the establishment of cellular immunity, which keeps these viruses under control for life. Far less is known about how these viruses influence B-cell responses.

OBJECTIVES

To evaluate the impact of latent EBV and CMV infection on rubella- and measles-specific antibody responses as well as on the B-cell compartment in a prospective birth cohort followed during the first 10 years of life.

METHODS

IgG titers against rubella and measles vaccines were measured in plasma obtained from the same donors at 2, 5, and 10 years of age. Peripheral B-cell subsets were evaluated ex vivo at 2 and 5 years of age. Factors related to optimal B-cell responses including IL-21 and CXCL13 levels in plasma were measured at all-time points.

RESULTS

EBV carriage in the absence of CMV associated with an accelerated decline of rubella and measles-specific IgG levels (p = 0.003 and p = 0.019, respectively, linear mixed model analysis), while CMV carriage in the absence of EBV associated with delayed IgG decay over time for rubella (p = 0.034). At 5 years of age, EBV but not CMV latency associated with a lower percentage of plasmablasts, but higher IL-21 levels in the circulation.

CONCLUSION

Our findings suggest that EBV carriage in the absence of CMV influences the B-cell compartment and the dynamics of antibody responses over time during steady state in the otherwise healthy host.

[Value of determining prostate specific antigen in follow-up of prostatic cancer]

The value of measuring serum prostate specific antigen (PSA) in monitoring cases of prostatic cancer was studied in 239 patients. 30 patients with benign prostatic hyperplasia served as controls. The patients were treated by radical prostatectomy, radiotherapy or chemotherapy. In the controls PSA levels were elevated in 60%, indicating that PSA measurement is not specific for prostatic cancer. Among 35 patients before and after radical prostatectomy, in those without disease progression, PSA levels were repeatedly low, but were elevated in all with progression. Among 25 patients after radiation and in 28 before and after radiation, low PSA levels were found in all those, without disease progression. High PSA levels, or a rise in levels after irradiation, preceded local growth or metastatic spread. In the 95 patients with metastatic spread who received hormone-and/or chemo-therapy, low PSA levels following initiation of treatment, were a favorable prognostic indicator, with a sensitivity of 100%. High levels, or a rise of levels after initiation of treatment indicated disease progression. The rise in PSA levels preceded clinical evidence of progression by 0 to 30 months. We conclude that serum PSA is a valuable marker for following patients with prostatic cancer.

Fifteen years' experience of combined hormone/chemotherapy in metastatic prostate cancer

Fifteen years ago we embarked on a treatment protocol for prostatic cancer patients with widespread disease (Stage D2) which included both hormonotherapy (i.e., orchiectomy and diethylstilbestrol [DES] 5 mg/day--later substituted with cyproterone acetate [CPA] 0.2 g/day) and chemotherapy (cyclophosphamide and 5-fluorouracil 10 mg/kg/week). The rationale for such an approach was the universally poor results obtained from the conventional approach which advocated consecutive single-treatment schedules once the previous therapy had ceased to be effective. As such a conventional approach probably allowed the selection of new resistant cell clones, we assumed that perhaps an aggressive combined systemic therapeutic approach from the start, would give such a group of patients--already with generalized disease--a better long-term result. In retrospect, after fifteen years, the chemotherapy on a series of 50 patients so treated has been well tolerated with only minimal, temporary side effects. This regimen was continued up to five years with a reduced maintenance dose. The hormonotherapy was also well tolerated, and was fully maintained. Only 28 percent died of their disease (16% within the first 2 years); 28 percent died of other causes; 40 percent are still alive (14% with clinical disease). In only 9 cases was the chemotherapy discontinued for various reasons. No control arm was originally designed in this protocol, but the long-term results suggest that our original concept was probably valid. Further studies, with the possible use also of newer chemotherapeutic agents, may well justify considering this combined therapeutic approach when dealing with this disease in its widespread form.

[Immunotherapy for metastatic renal cell carcinoma: treatment with PLAK cells and low-dose interleukin-2]

During the past 5 years publications from the NIH (Rosenberg et al.) and other centers have reported encouraging results in the treatment of metastatic renal cell carcinoma. Adoptive immunotherapy was applied, using lymphocytes activated by interleukin-2 (LAK cells) plus high doses of interleukin (IL-2) systemically. The mean clinical response rate was 20-35%. Severe lifethreatening adverse reactions to high doses of IL-2 were noted, although they were all of short duration. Laboratory findings of Novogrodsky et al. from Beilinson Medical Center, Israel showed that oxidizing mitogens can induce lymphocyte activation (PLAK cells). Further studies suggested that a combination of such activated cells with low doses of IL-2 could produce effective toxicity to tumor cells without the need for high doses of IL-2 which could be very toxic for the patient. In the past year we treated 7 patients with PLAK cells and IL-2. 4 completed the treatment, of whom 1 responded partially (regression of more than 50% of lung metastases), 1 is stable and in 1 liver metastases regressed but metastases in lumbar vertebrae and in the pelvis progressed. 1 patient died a month after discharge from hospital, probably due to rapid progression of the disease. Our protocol follows that of the Phase II clinical study of 40 patients treated at the Rogosin Institute, New York Hospital--Cornell Medical Center. The mean clinical response rate was 23.6%. Toxicity of IL-2 is dose-dependent. In this protocol, the low doses of IL-2 gave significantly fewer adverse reactions.

[Do asthmatic patients have deficits in symptom perception? Quasi-experimental and experimental findings on introception of airway obstruction]

Symptom perception of asthmatic patients was investigated in a quasi-experimental and in two experimental studies. Simultaneous ratings and measurements of airways obstruction assessed during an inhalative provocation test were correlated in the first study, in the two latter studies psychophysical parameters of the perception of external flow-resistive loads were determined for asthmatic patients and normal controls. These are the main results: 1. Most of the asthmatic patients are rather poor in discriminating provoked airways obstructions which results in a negative coping with the illness. 2. Asthmatic patients are slightly poorer in discriminating flow-resistive loads than healthy controls. 3. A distinct tendency of asthmatic patients to dissimulation found in the first study could not be confirmed in the two experiments.

The effect of intravesical bacillus Calmette-Guerin therapy on the upper urinary tract

A total of 66 patients with low grade, low stage transitional cell carcinoma of the bladder who were treated with intravesical bacillus Calmette-Guerin (BCG) underwent cystourethrography to detect vesicoureteral reflux. BCG was instilled weekly for 6 weeks and monthly thereafter for up to 24 months. Whenever vesicoureteral reflux was found or morphological abnormalities were detected on excretory urography (IVP) an isotope renal scan was performed to evaluate the relative renal function. Vesicoureteral reflux was found in 13 patients (19.7%): 10 had grades 1 and 2A, and 3 had grade 2B reflux. The number of BCG instillations ranged from 8 to 22. IVPs were normal in 11 patients. In 2 patients mild unilateral dilatation was present before BCG instillations, and this remained unchanged during and after therapy. None of the 13 patients with vesicoureteral reflux had IVP features suggestive of urinary tuberculosis. In 11 patients the refluxing renal systems had normal relative renal function (50 to 55%). Two patients had a decrease to 40% of the relative renal function with normal IVPs, suggesting a nonBCG related cause. We conclude that BCG therapy is safe in patients with minimal reflux.

Acute coronary events following cisplatin-based chemotherapy

Six patients with no previous signs or symptoms suggestive of coronary artery disease developed acute coronary ischemia/infarction shortly after cis-diamine-dichloroplatinum II (cisplatin) -based chemotherapy. In two patients this was the sole chemotherapeutic agent used. One patient underwent coronary angiography which disclosed no pathology, but following which, while on a calcium channel blocking agent regimen, he had an uneventful course of chemotherapy with cisplatin. Documentation of cisplatin-related vascular events is important in view of the growing number of patients who undergo cisplatin-based chemotherapy.

Economic impact of a computer-based centralized organization in a clinical laboratory

The Department of Laboratory Medicine, University of Washington, has explored various management of organizational approaches over the past seven years. The Centralized Processing Area supported by a computerized information system has evolved from these efforts. Despite a decrease in U.W. hospital usage since 1968-69, laboratory volume has steadily increased. The cost of these services is shown in relation both to three successive management systems and to the impact of inflation on laboratory costs. Chemistry and hematology costs per procedure, including administration and computer costs, are compared with microbiology cost per procedure, where the management system was not used. There is growing acceptance of the intangible benefits of computerization in the laboratory. Economic benefits are often presumed but have not been proven. Favorable economic effects of the Centralized Processing Area together with the computerized information system are demonstrated.

The behavior modification of a dentally disabled child

Parents of children afflicted with a dental handicap may experience difficulty in finding a dentist to treat their child. The dentist may be expected to assume the role of family confidant, because of the family's reluctance to seek other professional help. It is important to gain the early confidence and trust of the patient by techniques known to reduce the patient's fear. The patient can now interact more freely with his peers, because of the dental treatment which he has received. His trust, selfesteem, and confidence are much improved.