Search

Pensions are an important part of a state's social policy, in the future perspective of reporting sustainability in modern organizations and in the personal life of each person. The demographic tendency of the world's aging population brings attention to finding new effective solutions for the management of pension systems. The first interested in finding solutions is the state, because with the aging of the population, health and care expenses for the elderly will increase significantly, putting additional pressure on public budgets. Pensions are a major expense in the annual budget of a state, so the pension system has been diversified by introducing two new components: mandatory private pension and voluntary pension. The paper presents the administration and functioning of the state pension administered privately.

When a person reaches retirement age he wants to have the same standard of living as before retirement. The fundamental social function of the pension system is to ensure universal coverage, to provide decent pensions for retires, for those suffering from accidents at work or people who became ill and could no longer work. Achieving these goals is difficult due to many factors that influence each person's living conditions differently and applying the same conditions to everyone is often unfair and wrong. The main source of income that a person will have when he reaches the legal retirement age is the state pension. This will represent up to 50% of the income that the person had before retiring. There are countless factors that influence its level: gross income, contribution period, retirement conditions, economic situation, number of employees, number of retirees and legislation in the field. This paper will present general questions relating to social security, social insurance type, authorized institutions, and their evolution over the last years.

Laryngeal cancer continues to raise challenges for specialists all over the world even if there has been improvement in its diagnosis, therapeutic options and comprehensive view of the malignant tumor process. The decision of the oncological committee is not subject to the preferences of the patient, since in terms of therapy, this is the role of the specialist treating the patient. It is very important that the patient should know the implications of total surgery and that the patient has a poorer quality of life after total laryngectomy. The quality of life of these patients has been assessed by means of European quality of life questionnaires in terms of physical status and symptoms, social integration and psychoemotional status. The absence of voice, the impairment in swallowing, the esthetic impairment, the family and social reintegration need to be addressed by the oncological team so that the quality of life of these patients be at optimal levels. The specific questionnaires for the quality of life evaluation need to be used for any patient with laryngeal cancer and key points need to be addressed individually to meet each patient's expectations.

Locally advanced larynx cancer benefits from curative surgery therapy. Clinical trials have been proposed for assessing the quality of life for patients with larynx malignant neoplasia who underwent radical surgery. The removal of the “voice box” is known to have great impact on the social reintegration of these patients as well as psychological distress. The presence of tracheostomy and voice impairment are two of the major issues that need to be thought of by patients that will have a total laryngectomy. The quality of life is a multi-dimensional subjective and personal concept which includes normal physical activity, looks, psychological status, somatic symptoms and, non the less, sexual activity. Cancer free survival intervals for patients with larynx cancer must be evaluated physical and psychological modifications with particular considerations to stress, anxiety and depression related symptoms and to functional rehabilitation adaptation regarding swallowing and speech. Oncology surgeons must consider that QoL is impaired in all patients with larynx cancer that benefit from total laryngectomy. However, there is evidence presented below that the difference in QoL parameters is small when comparing radical surgery, total laryngectomy, and larynx conservation by radio and chemotherapy.

Profit is today one of the most pursued objectives of a business activity. A company is established in order to obtain profit from the activity that it develops. Profit is indirectly the state policy goal because it should encourage traders to make profits through tax measures or grants.

In countries in course of development, insurance has recently become a highly approached and exciting field, especially in the context of the financial crisis. The crisis had the opposite effect on people's attitude concerning the need for security, increasing their responsibility to assess possible risks. As a result of the market research I've made, I tried to identify aspects related to the approach of insurances in Romania, from the perspective of people who have signed contracts of life insurance.

Over time, people and their activities were subject to risk. These risks cause damage in different sizes and the insurances cover them, they permit the reconstruction of the destroyed property, ensuring the continuity of the production process and contribute to the integrity of national wealth. Through this paper we try to identify aspects of usability and security role in the development of society and social wellbeing.

Asigurarea exprima in principal o protectie financiara pentru pierderile suferite de oameni sau companii datorate unor diverse riscuri. Metodele de asigurare s-au dezvoltat o data cu nevoile de protective existente la un moment dat pentru oameni si afacerile acestora. Astfel oamenii de afaceri au inteles sa foloseasca asigurarea pentru a micsora riscurile ce pot aparea in tranzactiile comerciale si cele legate de protectia patrimoniului. Lucrarea se adreseaza, in primul rand, studentilor din invatamantul superior economic de stat si particular, elevilor din liceele cu profil economic, cadrelor didactice din invatamantul universitar si liceal, agentilor economici si institutiilor statului si oricaror alte persoane fizice sau juridice care doresc sa dobandeasca cunostinte in domeniul asigurarilor.

The insurances have become an extremely approached and exciting domain in the last years, especially in the context of financial crisis. It had a reverse effect on people’s attitude vis-a-vis the need of insurance. Through this paperwork I have tried to identify aspects related to the approach of insurances from the perspective of the people who have signed insurance contracts.

Hedge operations are particular stock market operations through which stock market traders, producers, intermediaries intend to cover the unfavorable outcome of the goods price on the cash market (physical). Price hedging by hedge operations is possible with the similarity and possible convergence between cash and futures prices. Since both markets are influenced by changes in the same general factors of market, prices tend to move in the same directions, but not necessarily with the same magnitude. The exposure rank to price risk which can be minimized depends on the correlation rank between the cash price changes and the future prices variations. Hedgers manage to decrease losses by using this type of transaction.

The tax evasion is and has been a controversial phenomenon over time. Specialists in finance and the competent bodies of the village have always tried to find measures to control and limit this. In this paper, the authors aim to present the motivations behind the tax evasion. They seek both personal considerations and opportunities offered by the current legislation. The state of satiation of man and his daily comfort are perhaps the most important barometers in the analysis of the tax evasion. We don't have to neglect also the aspect of the pressure put by the state through its fiscal and budgetary policy, which creates discomfort and willingness to violate the legal rules in certain situation.

Fragmentation is a degradation pathway ubiquitously observed in proteins despite the remarkable stability of peptide bond; proteins differ only by how much and where cleavage occurs. The goal of this review is to summarize reports regarding the non-enzymatic fragmentation of the peptide backbone of monoclonal antibodies (mAbs). The sites in the polypeptide chain susceptible to fragmentation are determined by a multitude of factors. Insights are provided on the intimate chemical mechanisms that can make some bonds prone to cleavage due to the presence of specific side-chains. In addition to primary structure, the secondary, tertiary and quaternary structures have a significant impact in modulating the distribution of cleavage sites by altering local flexibility, accessibility to solvent or bringing in close proximity side chains that are remote in sequence. This review focuses on cleavage sites observed in the constant regions of mAbs, with special emphasis on hinge fragmentation. The mechanisms responsible for backbone cleavage are strongly dependent on pH and can be catalyzed by metals or radicals. The distribution of cleavage sites are different under acidic compared to basic conditions, with fragmentation rates exhibiting a minimum in the pH range 5 to 6; therefore, the overall fragmentation pattern observed for a mAb is a complex result of structural and solvent conditions. A critical review of the techniques used to monitor fragmentation is also presented; usually a compromise has to be made between a highly sensitive method with good fragment separation and the capability to identify the cleavage site. The effect of fragmentation on the function of a mAb must be evaluated on a case-by-case basis depending on whether cleavage sites are observed in the variable or constant regions, and on the mechanism of action of the molecule.

IgG monoclonal antibodies (mAbs) consist of two Fab fragments and one Fc fragment. The Fab fragments contain the variable regions and are responsible for drug specificity (via antigen binding); the Fc fragment contains constant regions and is responsible for effector functions (via interactions with Fcγ receptors) and extended serum half-life (via interaction with the neonatal Fc receptor, FcRn). There are two conserved methionine (Met) residues located in the FcRn binding site of the Fc fragment. It has been shown previously that oxidation of these two Met residues decreases the binding affinity to FcRn. We have further evaluated the impact of Met oxidation on serum half-lives of two humanized IgG1 mAbs in transgenic mice with human FcRn. Variable oxidation levels were obtained by several procedures: exposure to an oxidizing agent, accumulation during extended refrigerated storage, or chromatographic separation. Our results show that Met oxidation can result in a significant reduction of the serum circulation half-life and the magnitude of the change correlates well with the extent of Met oxidation and changes in FcRn binding affinities. The relatively low levels of Met oxidation accumulated during 3 years of refrigerated storage had minimal impact on FcRn binding and no detectable impact on the serum half-life.

Writing this article, the author proposes to make a brief presentation of the categories of indicators which determine the economic efficiency of the activity developed by the insurance companies from Romania and European Union. In the analyze of the activity efficiency of an insurance company it is followed the application of the same evaluation principles of the performance of each company. The application of the indicators is used to establish the most profitable report between the cashed premiums and the paid claims.

The article proposes to present a comparative analyze of two life insurance products of the most important insurance company from the Romanian market. The comparison focuses on a life insurance with capitalization and an investment plan. The two products analyzed includes the presentation of the financial aspects, especially, and the estimated profit of the products.

Chromatographic separation plays a key role in the identification, quantification, and characterization of protein variants. Here we describe separation of species containing two post-translational modifications (glycosylation and methionine oxidation) in the Fc fragment of a monoclonal antibody. The method is based on cation-exchange chromatography under mildly acidic conditions that destabilize mainly the CH2 domain. Our data suggest that the separation is not mediated by the chemical modification itself, but rather by subtle structural changes induced by the chemical modification in the domain-decoupled conformation that monoclonal antibodies adopt around pH 4. Compared to other procedures already described in the literature, this method demonstrates an improved separation and allows purification of species in the native fold for additional functional characterization. This approach of separation under conditions where the protein assumes an alternative conformation could find a more general utility for the separation of chemical modifications in proteins.

Despite technological advances, detection of deamidation in large proteins remains a challenge and the use of orthogonal methods is needed for unequivocal assignment. By a combination of cation-exchange separation, papain digestion, and a panel of mass spectrometry techniques we identified asparagine deamidation in light chain complementarity determining region 1 (CDR1) of a humanized IgG1 monoclonal antibody. The reaction yields both Asp and isoAsp, which were assigned by Edman degradation and by isoAsp detection using protein isoaspartate methyltransferase. The deamidated antibody variants were less potent in antigen binding compared to the nondegraded antibody. Changes in near-UV CD spectra, susceptibility to papain cleavage in an adjacent CDR2 loop, and the tendency of the newly formed isoAsp to undergo isomerization suggest local perturbations in the structure of the isoAsp-containing antibody.

The hinge region of human IgG2 contains four cysteine residues involved in disulfide linkages between the heavy chains, as well as the heavy and light chains. These linkages provide the fundamental framework of three distinct IgG2 disulfide isoforms recently described. Here, we detail another, disulfide-related post-translational modification in a recombinant variant of human IgG2. Heterogeneity associated with this antibody was separated into several fractions by anion-exchange chromatography (AEX), which is an important initial step that highlights the resolving power of surface charge-based HPLC techniques. Mass spectrometry of the intact antibody revealed weakly resolved discrete covalent additions of 25-35 Da in one of the two main AEX fractions. Digestion by endoproteinase Lys-C performed under nonreducing conditions, as well as tandem MS experiments, narrowed the modification to the peptide-containing disulfide-bridged hinge structure. High mass resolution and accuracy measurements of the peptide strongly suggested an addition of one or two S atoms. The modification could be eliminated by a mild reducing treatment of the intact antibody. Overall, these findings are consistent with the replacement of up to two disulfide bridges (S-S) with a like number of trisulfides (S-S-S) in the antibody hinge. The trisulfide modification is rather uncommon for proteins and its possible origins in the IgG2 variant are discussed.

The effects of secondary structure on asparagine (N) deamidation in a 22 amino acid sequence (369-GFYPSDIAVEWESNGQPENNYK-390) of the crystallizable (Fc) fragment of a human monoclonal antibody (Fc IgG1) were investigated using high-resolution ultra performance liquid chromatography with tandem mass spectrometry (UPLC/MS). Samples containing either the intact Fc IgG (∼50 kD) (“intact protein”), or corresponding synthetic peptides (“peptide”) were stored in Tris buffer at 37°C and pH 7.5 for up to forty days, then subjected to UPLC/MS analysis with high energy MS1 fragmentation. The peptide deamidated only at N382 to form the isoaspartate (isoD382) and aspartate (D382) products in the ratio of ∼4:1, with a half-life of ∼3.4 days. The succinimide intermediate (Su382) was also detected; deamidation was not observed for the other two sites (N387 and N388) in peptide samples. The intact protein showed a 30-fold slower overall deamidation half-life of ∼108 days to produce the isoD382 and D387 products, together with minor amounts of D382. Surprisingly, the D382 and isoD387 products were not detected in intact protein samples and, as in the peptide samples, deamidation was not detected at N388. The results indicate that higher order structure influences both the rate of N-deamidation and the product distribution.

The article refers to an analyze concerning the efficiency of the activity of Romanian insurance companies. In the analyze of the insurance companies it is taken into consideration their size, determined by the structure of the social capital, the number of employees and the number of locations. The indicators presented refer to the entire insurance market, generating therefore a full image of the analyzed phenomenon.

One major concern with biosimilars is that small differences compared with reference products might lead to unforeseen immunogenicity, thus affecting patient safety and drug efficacy. Differences could be due to either post-translational modifications of the therapeutic protein and/or to traces of impurities from the manufacturing process. The results presented in this communication illustrate the efforts to assess "biosimilarity" of a biosimilar candidate to a reference product for a specific group of process-related impurities, the host cell proteins (HCP). Extensive characterization of HCP in the drug substance of a biosimilar candidate revealed the identity of HCP copurifying with the protein of interest and guided process development to improve overall HCP clearance in the downstream process. The data presented illustrate the challenge of matching the reference product on either quantitative or qualitative aspects of HCP impurities.

Clinical-epidemiological investigations for further assessing the importance of video-assisted thoracoscopy in the treatment y of patients with neoplastic pleurisy.The researches included a group of 72 patients (31.9% men and 68.1% women aged 31-81 years, mean age ± 60 years) with neoplastic pleurisy who underwent pleural symphysis by video-assisted thoracoscopic talcage. For statistical-mathematical processing and interpretation the Pearson correlation index with the level of significance at p = 0.05 and highly significant at p0.005 was used.Neoplastic pleurisy prevalently affected the age groups 51-80 years (84.9%). Dyspnea was present in all cases, and patient history at the time of admission revealed 14 conditions, of which 25% were lung cancers. Macroscopically nodular and vegetative tumors were found in 66.7% of cases. An amount of 1000-2000 ml of pleural fluid was found in 44.5% of the cases and a serocitrin appearance in 50%. In 23.6% of the cases cytology results were positive for malignancy and in 13.8% suspicious. In 65.2% of the cases the pleural fluid was exudative and anatomopathology was suggestive of adenocarcinoma in 34.7% of the cases and breast cancer in 18%. The prevalence of recurrences varied from 1 month to more than 7 months, with 36.4% for 1-2 months.The obtained additional data support the important role of pleural symphysis by video-assisted thoracoscopic talcage in the patients with neoplastic pleurisy.

To determine the relationship between the characteristics of a group of lung cancer patients, lung cancer surgeries, and the incidence of early and/or late postoperative complications.The study included a group of 115 lung cancer patients aged 40 to 85 years, 76.5% men, 60.91% living in urban areas, who received surgical treatment in the interval January 2013-August 2014. Data were collected from electronic medical records and survey sheets and processed and interpreted using Pearson correlation index (p-value of 0.05 was considered statistically significant and of0.005 highly statistically significant), and chi2, y, 1c = 25% tests. All statistical analyses were performed using the SPSS statistical software package version 13.0.Of the 115 patients 7.8% were in the 40-50 years age group and 87.8% in the 51-75 years age group (por = 0.001). Most patients were males (76.5%, p0.001), and 60.9% of the patients were living in urban areas (por = 0.05). The difference in the prevalence of smokers (76.5%) vs. non smokers (23.5%) was highly statistically significant (p0.005). Active smoking of one pack of cigarettes per day for more than 10 years was recorded in 54.8%. The presence of co morbidities (17 events) and the distribution of neoplastic lesions in the five anatomical areas required the performance of lobectomies, bilobectomies or pneumectomies. The incidence of early (14 entities) and late postoperative complications (7 entities) depended on patient's general condition, nature of co morbidities, location and stage of neoplastic lesions, and surgical complexity.Lung cancer, in various locations and stages, most commonly affected males aged 40-85 years, from urban areas, smokers, with various co morbidities. Surgeries performed in these patients were often laborious and with a relatively low incidence of postoperative complications.

We report the preparation and the immunogenicity of a conjugate vaccine obtained by chemically conjugating a variant of the extracellular peptide fragment of influenza type A M2 protein to the human papillomavirus (HPV) viruslike particle (VLP). Conjugates comprised of approximately 4,000 copies of the antigenic peptide per VLP are obtained as the result of the reaction between a C-terminal cysteine residue on the peptide and the maleimide-activated HPV VLP. The resulting conjugates have an average particle size slightly larger than the carrier and present enhanced overall stability against chemical and thermal-induced denaturation. The M2-HPV VLP conjugates lost the binding affinity for anti-HPV conformational antibodies but retained reactivity to a M2-specific monoclonal antibody. The conjugate vaccine formulated with aluminum adjuvant and delivered in two doses of 30-ng peptide was found to be highly immunogenic and conferred good protection against lethal challenge of influenza virus in mice. These results suggest that HPV VLP can be used as a carrier for synthetic or small antigens for the development of subunit vaccines.

Conventional influenza vaccines can prevent infection, but their efficacy depends on the degree of antigenic “match” between the strains used for vaccine preparation and those circulating in the population. A universal influenza vaccine based on invariant regions of the virus, able to provide broadly cross-reactive protection, without requiring continuous manufacturing update, would solve a major medical need. Since the temporal and geographical dominance of the influenza virus type and/or subtype (A/H3, A/H1, or B) cannot yet be predicted, a universal vaccine, like the vaccines currently in use, should include both type A and type B influenza virus components. However, while encouraging preclinical data are available for influenza A virus, no candidate universal vaccine is available for influenza B virus. We show here that a peptide conjugate vaccine, based on the highly conserved maturational cleavage site of the HA 0 precursor of the influenza B virus hemagglutinin, can elicit a protective immune response against lethal challenge with viruses belonging to either one of the representative, non-antigenically cross-reactive influenza B virus lineages. We demonstrate that protection by the HA 0 vaccine is mediated by antibodies, probably through effector mechanisms, and that a major part of the protective response targets the most conserved region of HA 0 , the P1 residue of the scissile bond and the fusion peptide domain. In addition, we present preliminary evidence that the approach can be extended to influenza A virus, although the equivalent HA 0 conjugate is not as efficacious as for influenza B virus.

A universal influenza virus vaccine that does not require frequent updates and/or annual immunizations will offer significant advantages over current seasonal flu vaccines. The highly conserved influenza virus A M2 membrane protein has been previously suggested as a potential antigen target for such a vaccine. Here, we report systematic evaluation of M2 peptide conjugate vaccines (synthetic peptides of M2 extracellular domain conjugated to keyhole limpet hemocyanin (KLH) or Neisseria meningitidis outer membrane protein complex (OMPC)) in mice, ferrets, and rhesus monkeys. The conjugate vaccines were highly immunogenic in all species tested and were able to confer both protection against lethal challenge of either H1N1 or H3N1 virus in mice and reduce viral shedding in the lower respiratory tracts of mice and ferrets. The protection against lethal challenge in mice could also be achieved by passive transfer of monkey sera containing high M2 antibody titers. In addition, we showed that M2 antisera were cross reactive with M2 peptides derived from a wide range of human influenza A strains, but they failed to react with M2 peptides of the pathogenic H5N1 virus (A/Hong Kong/97). The data presented here will permit better understanding of the potential of an M2-based vaccine approach.

Spectroscopic studies have been performed to characterize the solution structure of the V66W mutant of Staphylococcal nuclease and the corresponding 1-136 fragment, referred to as V66W'. Whereas wild-type nuclease has a single tryptophan residue at position 140, the V66W mutant has a second tryptophan residue at position 66, which is the only such residue in V66W'. Steady-state and time-resolved fluorescence studies show Trp-66 in V66W' to have a blue emission, a relatively large fluorescence quantum yield, a long lifetime, a significant degree of protection from solute quenchers, and to depolarize with a relatively long rotational correlation time. These results characterize Trp-66 in V66W' as being a buried residue, which indicates that this fragment retains some global structure. Circular dichroism (CD) data are consistent with the fragment having lost most of the alpha-helical content of the wild type, while retaining beta-sheet structure. The CD spectrum in the aromatic region also suggests that Trp-66 in the fragment experiences an asymmetric environment, which is not identical to that in the full length mutant, V66W. In addition, optical detection of triplet state magnetic resonance (ODMR) spectroscopy can clearly resolve the tryptophan residues and demonstrates differences between the local environment of Trp-66 in V66W and in V66W', as well as small differences in the Trp-140 environment in wild type and in V66W. Guanidine-HCl induced and thermally induced unfolding studies were performed by simultaneously acquiring CD and fluorescence data as a function of the perturbation and then performing a global analysis of such multiple data sets in terms of two-state and three-state unfolding models. Whereas data for wild-type nuclease and the V66W' fragment are well characterized by a two-state unfolding model, data for the V66W mutant are better characterized by a three-state process. That is, both the denaturant- and temperature-induced unfolding of V66W involves the significant population of an equilibrium unfolding intermediate. Our global analyses yield thermodynamic parameters for the unfolding transitions, and we show that the data for V66W can be described by a constrained three-state model in which the transition of the intermediate to the fully unfolded state is fixed to have the same thermodynamic parameters that describe the unfolding of the V66W' fragment.

Binding of sodium dodecyl sulfate (SDS) to bovine serum albumin (BSA) and human serum albumin (HSA) in aqueous solutions at room temperature induces significant changes in the phosphorescence lifetime of tryptophan (Trp) residues. A steep rise of the phosphorescence lifetime from 1.9 ms to 10.0 ms for BSA and from 1.9 ms to 5.5 ms for HSA is observed when the total SDS concentration increases from 0.0 mM to 0.22 mM at 1 mg/mL protein concentration. As the total SDS concentration is further increased to 2.2 mM, a slower increase in the phosphorescence lifetime is observed, from 10.0 ms to 19.5 ms for BSA and from 5.5 ms to 7.2 ms for HSA. It appears that the phosphorescence lifetime modifications are mainly due to an increase of protein matrix rigidity around Trp residues. The observed differences (between HSA and BSA) allow us to distinguish the contribution of the two Trp residues to the BSA phosphorescence.

Paolo Ingallinella, Elisabetta Bianchi, Xiaoping Liang, Marco Finotto, Michael Chastain, Jiang Fan, Tong-Ming Fu, Hong Chang Song, Melanie Horton, Daniel Freed, Walter Manger, Emily Wen, Li Shi, Roxana Ionescu, Colleen Price, Marc Wenger, Emilio Emini, Riccardo Cortese, Gennaro Ciliberto, John Shiver and Antonello Pessi IRBM P.Angeletti, Pomezia (Rome), Italy; Merck Research Laboratories, West Point, PA, USA

This article describes a method to analyze the kinetics of monoclonal antibody degradation and to determine the quantitative relationship between the degradation rates observed at the molecular and peptide levels. The proposed model can be applied to any degradation pathway that can be well approximated by a first order reaction; if several pathways exist, the model assumes that they are independent. Three examples are presented to illustrate the benefits of this approach. For each case, the calculated fractions of species were compared to one or more data sets to demonstrate the good agreement between experimental results and model prediction. This method can serve as a valuable tool in interpreting chromatograms of degraded samples and predicting the population of species present at the molecular level when only data from degradation observed at the peptide level is available. This method further demonstrates how deviations from predictions of simple models can be used to unravel additional, unforeseen reactions.

The expanding field of monoclonal antibody-based pharmaceuticals has triggered increased interest in analytical characterization of these large proteins and in understanding of their heterogeneity and degradation pathways. As a result, a large number of enzymatic modifications as well as chemical and physical degradations have been reported in monoclonal antibodies in recent years. Most heterogeneity is related to changes in the surface charge of the antibody, either directly, as a change in the number of charged residues, or indirectly as a chemical or physical alteration that changes surface-charge distribution. This review presents an overview of the sources of charge-related heterogeneity in monoclonal antibodies and the methods used for their detection. A detailed section is dedicated to deamidation of asparagine and isomerization of aspartic acid residues, two ubiquitous degradation pathways detected in antibodies and other proteins as well. Finally, kinetic modeling of the accumulation of antibody variants is presented as a tool to determine the expected fraction of molecules that have undergone one or more degradation reactions.

Temperature-induced unfolding of three humanized IgG1 monoclonal antibodies and their Fab and Fc fragments was monitored by differential scanning calorimetry at neutral pH. With some exceptions, the thermogram of the intact antibody presents two peaks and the transition with the larger experimental enthalpy contains the contribution from the Fab fragments. Although the measured enthalpy was similar for all three Fab fragments studied, the apparent melting temperatures were found to vary significantly, even for Fab fragments originating from the same human germline. Therefore, we propose to use the measured enthalpy of unfolding as the key parameter to recognize the unfolding events in the melting profile of an intact IgG1 antibody. If the variable domain sequences, resulting from complementarity determining regions (CDRs) grafting and humanization, destabilize the Fab fragment with respect to the CH3 domain, the first transition represents the unfolding of the Fab fragment and the CH2 domain, while the second transition represents CH3 domain unfolding. Otherwise, the first transition represents CH2 domain unfolding, and the second transition represents the unfolding of the Fab fragment and the CH3 domain. In some cases, the DSC profile may present three transitions, with the Fab unfolding occurring at distinct temperatures compared to the melting of the CH2 and CH3 domains. If the DSC profile of a humanized IgG1 monoclonal antibody cannot be described by the model above, the result may be an indication of significant structural heterogeneity and/or of disruption of the Fab cooperative unfolding. Low stability or heterogeneity of the Fab fragment may prove problematic for long-term storage or consistency of production. Therefore, understanding the features of a DSC profile is important for clone selection and process maturation in the early stages of development of therapeutic monoclonal antibodies. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1414–1426, 2008