Attribute Analytics Performance Metrics from the MAM Consortium Interlaboratory Study

The multi-attribute method (MAM) was conceived as a single assay to potentially replace multiple single-attribute assays that have long been used in process development and quality control (QC) for protein therapeutics. MAM is rooted in traditional peptide mapping methods; it leverages mass spectrometry (MS) detection for confident identification and quantitation of many types of protein attributes that may be targeted for monitoring. While MAM has been widely explored across the industry, it has yet to gain a strong foothold within QC laboratories as a replacement method for established orthogonal platforms. Members of the MAM consortium recently undertook an interlaboratory study to evaluate the industry-wide status of MAM. Here we present the results of this study as they pertain to the targeted attribute analytics component of MAM, including investigation into the sources of variability between laboratories and comparison of MAM data to orthogonal methods. These results are made available with an eye toward aiding the community in further optimizing the method to enable its more frequent use in the QC environment.

New Peak Detection Performance Metrics from the MAM Consortium Interlaboratory Study

The Multi-Attribute Method (MAM) Consortium was initially formed as a venue to harmonize best practices, share experiences, and generate innovative methodologies to facilitate widespread integration of the MAM platform, which is an emerging ultra-high-performance liquid chromatography-mass spectrometry application. Successful implementation of MAM as a purity-indicating assay requires new peak detection (NPD) of potential process- and/or product-related impurities. The NPD interlaboratory study described herein was carried out by the MAM Consortium to report on the industry-wide performance of NPD using predigested samples of the NISTmAb Reference Material 8671. Results from 28 participating laboratories show that the NPD parameters being utilized across the industry are representative of high-resolution MS performance capabilities. Certain elements of NPD, including common sources of variability in the number of new peaks detected, that are critical to the performance of the purity function of MAM were identified in this study and are reported here as a means to further refine the methodology and accelerate adoption into manufacturer-specific protein therapeutic product life cycles.

A light, nontoxic interleukin 12 protocol inhibits HER-2/neu mammary carcinogenesis in BALB/c transgenic mice with established hyperplasia

With a slight asynchronous but consistent progression, all of the mammary glands of female BALB/c mice transgenic for the transforming rat HER-2/neu oncogene progress to atypical hyperplasia and to invasive carcinoma. Previous studies have shown that chronic administration of interleukin (IL) 12 started at the 2nd week of age hampers this progression because of its ability to inhibit tumor angiogenesis and activate a nonspecific immune response. Here we show that a similar inhibition is achieved when 7-week-old mice with fully blown atypical hyperplasia receive a weekly injection of 100 ng IL-12 for 16 times. This lower-dose and later IL-12 administration induces high and sustained levels of serum IFN-gamma equivalent to those elicited by more frequent administrations. A lower-dose and less toxic treatment may thus be envisaged as a possible option in the management of preneoplastic mammary lesions.

Inhibition of mammary carcinogenesis by systemic interleukin 12 or p185neu DNA vaccination in Her-2/neu transgenic BALB/c mice

Because BALB/c mice transgenic for the rat Her-2/neu oncogene develop multifocal carcinomas in all mammary glands by week 33, they constitute an aggressive model for investigation of treatments designed to oppose mammary carcinogenesis. Nonspecific immune reaction elicited by systemic interleukin (IL)-12 both delayed the appearance of the first tumor and reduced the number of glands affected. However, only 5% of mice were tumor free at week 33. On the other hand, specific vaccination with plasmids encoding for the rat p185neu resulted in a further delay, so much so that 58% of mice were tumor free at week 33. No CTL response was evoked in either IL-12-treated or DNA-vaccinated mice, whereas an anti-rat p185neu antibody response was evident in the latter. Pathological examinations showed that in both IL-12-treated and DNA-vaccinated mice, the tumor growth area was infiltrated by reactive cells associated with expression of endothelial adhesion molecules and antiangiogenic proinflammatory cytokines. In the vaccinated mice, reduction of the number of cells expressing rat p185neu was combined with down-regulation of its membrane expression and even a marked inhibition in development of the terminal ductal lobular units. The reactive infiltrate in vaccinated mice contained numerous granulocytes that likely played an antiangiogenic and angiodestructive role and also joined other cells in the antibody-mediated killing of the r-p185neu+ cells. These results suggest that the elicitation of nonspecific and specific immunity could be beneficially used in individuals with a high risk of developing tumors.

Insertion of the DNA for the 163-171 peptide of IL1beta enables a DNA vaccine encoding p185(neu) to inhibit mammary carcinogenesis in Her-2/neu transgenic BALB/c mice

An assessment was made of the effectiveness of DNA vaccination in prevention of the mammary adenocarcinomas of BALB/c female mice transgenic for the activated rat Her-2/neu oncogene. Atypical hyperplasia is evident in their mammary glands when they are 6 weeks old and in situ carcinoma by the 13th week. Palpable invasive carcinomas appear around the 17th week and are always evident in all 10 glands by the 33rd week. Intramuscular vaccinations with 100 microg plasmid DNA encoding the extracellular domain of the Her-2/neu p185 (ECD) performed at the 6th, 12th, 18th and 24th week provided no significant protection, whereas those ECD plasmids in which the DNA coding for the immunomodulatory 163-171 (VQGEESNDK) nonapeptide of human IL1beta (ECD-IL1betap) had been inserted both delayed carcinogenesis and reduced tumor multiplicity. This reduction was associated with a marked immune-inflammatory reaction and a conspicuous leukocyte infiltrate located in the stroma surrounding the hyperplastic mammary ductul-alveolar structures. It was also directly correlated with a high anti-p185(neu) antibody production and an immunoglobulin switch to IgG2a and IgA. No anti-p185(neu) cytotoxic response was found. No significant protection was obtained when the DNA coding for the non-active peptide 189-197 of IL1beta was inserted.

DNA vaccination against rat her-2/Neu p185 more effectively inhibits carcinogenesis than transplantable carcinomas in transgenic BALB/c mice

The ability of vaccination with plasmids coding for the extracellular and the transmembrane domain of the product of transforming rat Her-2/neu oncogene (r-p185) to protect against r-p185(+) transplantable carcinoma (TUBO) cells and mammary carcinogenesis was evaluated. In normal BALB/c mice, DNA vaccination elicits anti-r-p185 Ab, but only a marginal CTL reactivity, and protects against a TUBO cell challenge. Massive reactive infiltration is associated with TUBO cell rejection. In BALB/c mice transgenic for the rat Her-2/neu gene (BALB-neuT), DNA vaccination elicits a lower anti-r-p185 Ab response, no CTL activity and only incompletely protects against TUBO cells, but markedly hampers the progression of carcinogenesis. At 33 wk of age, when control BALB-neuT mice display palpable tumors in all mammary glands, about 60% of immunized mice are tumor free, and tumor multiplicity is markedly reduced. Tumor-free mammary glands still display the atypical hyperplasia of the early stages of carcinogenesis, and a marked down-modulation of r-p185, along with a massive reactive infiltrate. However, BALB-neuT mice protected against mammary carcinogenesis fail to efficiently reject a TUBO cell challenge. This suggests that the mechanisms required for the rejection of transplantable tumors may not coincide with those that inhibit the slow progression of carcinogenesis.

A phase I/II trial of HIV SF2 gp120/MF59 vaccine in seronegative thais.AFRIMS-RIHES Vaccine Evaluation Group. Armed Forces Research Institute of Medical Sciences and the Research Institute for Health Sciences

Fifty-two human immunodeficiency virus type 1, seronegative Thai adults from the community were enrolled in a double-blind, placebo controlled, phase I/II trial of HIV SF2 gp120/MF59 vaccine to determine the safety and immunogenicity of this recombinant, B clade, HIV envelope protein vaccine. Twenty-six subjects were enrolled at each of two sites in Thailand, Bangkok and Chiang Mai. Twelve subjects received placebo and 40 subjects received vaccine (50 microg). Subjects were immunized according to one of two schedules, 0, 1 and 4 or 0, 1 and 6 months. The frequency of adverse reactions was not different between placebo and vaccine subjects, nor between immunization schedules. Of vaccinees, all developed high-titer binding antibody to the immunogen (rgp120), 39 developed neutralizing antibody (NA) responses against homologous virus (HIV-1(SF2)), and 22 developed NA against heterologous virus (HIV-1(MN)). No subject demonstrated intercurrent HIV infection, however screening EIA reactivity occurred in 27% of recipients. Thus, this candidate HIV vaccine was found to be safe and immunogenic in Thai adults, laying the foundation for development of a subtype E construct in this population.

Ability of systemic interleukin-12 to hamper progressive stages of mammary carcinogenesis in HER2/neu transgenic mice

Previous studies in mice have shown that chronic administration of recombinant interleukin-12 (IL-12) hampers the progression of both chemical- and oncogene-dependent carcinogenesis. This suggests that a new preventive strategy may be envisaged for individuals with a genetic risk of cancer or carrying preneoplastic lesions. Starting at progressive stages of mammary carcinogenesis, female BALB/c and FVB mice carrying the activated rat HER2/neu oncogene (BALB-neuT) or the proto-oncogene (FVB-neuN) under the mouse mammary tumor virus promoter received multiple 5-day courses of different doses of IL-12. The times of tumor appearance, multiplicity, and histopathological features of the neoplastic lesions were evaluated. In both BALB-neuT and FVB-neuN mice, 5-day i.p. courses of 50/100 ng of IL-12/day inhibited mammary carcinogenesis when they coincided with the progression of early preneoplastic lesions. Inhibition appears to depend primarily on the ability of IL-12 to interfere with early tumor angiogenesis. Later treatments are much less effective, and daily doses of 10 and 2 ng are useless. The efficacy of early IL-12 courses suggests that they could be used to prevent mammary tumors in individuals at risk, whereas their lower efficacy in later stages of carcinogenesis and the dose range required pose some constraints on their use in the management of overt preneoplastic lesions. Precise understanding of tumor progression means that effective treatments can be commenced relatively late in the life of individuals at risk and that no lifetime administration is required.

Analysis of mammary carcinoma onset and progression in HER-2/neu oncogene transgenic mice reveals a lobular origin

Morphologic examinations of mammary neoplasias arising in BALB/c (H-2d) mice carrying the activated rat HER-2/neu oncogene (BALB-NeuT), and in FVB (H-2q) mice bearing the wild-type proto-oncogene (FVB-NeuN), indicate that both conditions result in a very human-like lobular carcinoma of alveolar type, whose histotype is the result of the preferential expression of HER-2/neu products in the epithelium of lobular ducts and lobules. Detailed analysis of tumor progression indicates that transition from lobular hyperplasia to overt carcinoma is associated with a high epithelial proliferation rate, as assessed by anti-proliferating cell nuclear antigen immunostaining, and coincides with the activation and maximal extension of tumor angiogenic process as assessed by microvessel count (anti-CD31), anti-beta3 integrin, and anti-laminin immunostaining. Neovascularization is accompanied by vascular endothelial cell growth factor and basic fibroblast growth factor production by hyperplastic epithelial cells. By contrast with the BALB-NeuT tumors, E-cadherin expression is almost nonexistent in those arising in FVB-NeuN mice and this may explain their high metastatic potential. Despite their different kinetics, however, the lung metastases observed in both strains are histologically similar and resemble the primary tumor. Both strains can thus be proposed as models for "in vivo" investigation of the origin and progression of the alveolar type of lobular mammary carcinoma and the testing of new therapeutic approaches.

Cytokine gene-engineered vaccines

Cytokines modulate immune reactivity and have therefore been used to build cancer vaccines. Experimental vaccination of rodents and humans with cytokine-gene engineered tumor cells, fusion proteins between cytokines and tumor antigens, and their DNA have been shown to induce a significant immune memory, even against poorly immunogenic tumors. This immune memory can prevent tumor growth and cure initial metastases, but is poorly effective against established tumors. To date clinical trials have been confined to patients with advanced tumors; so far they suggest that this approach is safe.

Interleukin 12-mediated prevention of spontaneous mammary adenocarcinomas in two lines of Her-2/neu transgenic mice

The ability of interleukin (IL)-12 to prevent tumors when administered to individuals with a genetic risk of cancer was studied in two lines of transgenic mice expressing rat HER-2/neu oncogene in the mammary gland. Female BALB/c (H-2(d)) mice carrying the activated HER-2/ neu oncogene show no morphological abnormalities of the mammary gland until 3 wk of age. They then progress through atypical hyperplasia to in situ lobular carcinoma and at 33 wk of age all 10 mammary glands display invasive carcinomas. Adult FVB mice (H-2(q)) carrying the HER-2/neu protooncogene develop mammary carcinomas with a longer latency (38-49 wk) and a lower multiplicity (mean of 2.6 tumors/mice). Treatment with IL-12 (5 daily intraperitoneal injections, 1 wk on, 3 wk off; the first course with 50 ng IL-12/day, the second with 100 ng IL-12/day) begun at 2 wk of age in BALB/c mice and at 21 wk of age in FVB mice markedly delayed tumor onset and reduced tumor multiplicity. Analogous results were obtained in immunocompetent and permanently CD8(+) T lymphocyte-depleted mice. In both transgenic lines, tumor inhibition was associated with mammary infiltration of reactive cells, production of cytokines and inducible nitric oxide synthase, and reduction in microvessel number, in combination with a high degree of hemorrhagic necrosis.