Comparative studies of monkey and human immunoglobulins

Lymphocyte subsets and immunoglobulin levels in peripheral blood from cynomolgus monkeys (Macaca fascicularis) of different age groups

Immunotoxicity assessment is an important part of non-clinical safety evaluation of biotechnology-derived pharmaceuticals. The reference ranges of evaluated parameters, which depend on the sex, age and geographical origin of animals, play a significant role in interpreting the study results. The aim of this study was to determine the reference ranges of parameters commonly used for non-clinical immunotoxicity studies in cynomolgus monkeys (Macaca fascicularis) of different ages. The percentages of CD3⁺, CD4⁺, CD8⁺, CD20⁺, CD16/56⁺ lymphocytes, and the serum levels of immunoglobulins A, M, G and E in clinically healthy cynomolgus monkeys of both sexes and different ages (37-104 months) were analysed. The lymphocyte subsets were assessed by flow cytometry and serum immunoglobulin levels were determined by enzyme-linked immunosorbent assay. Statistical analysis showed a weak rank correlation of CD3⁺, CD20⁺ lymphocyte levels with the ages of female and male cynomolgus monkeys, and no significant correlation with age for the combined data of both sexes. The serum levels of immunoglobulins A, M, G and E did not have a significant rank correlation with age for the combined data of both sexes, whereas IgA levels in females and IgG levels in males were weakly correlated with age. Overall, these results justify the use of animals aged three to eight years for non-clinical immunotoxicity evaluation of biotechnology-derived pharmaceuticals. It is important to avoid the formation of animal groups with extreme ages (three years or eight years) in one group during randomization.

Isotyping and Semi-Quantitation of Monkey Anti-Drug Antibodies by Immunocapture Liquid Chromatography-Mass Spectrometry

There is an urgent demand to develop new technologies to characterize immunogenicity to biotherapeutics. Here, we developed an immunocapture LC-MS assay to isotype and semi-quantify monkey anti-drug antibodies (ADAs) to fully human monoclonal antibody (mAb) drugs. ADAs were isolated from serum samples using an immunocapture step with the Fab of the full-length mAb cross-linked to magnetic beads to minimize matrix interference. A positive monoclonal antibody control against the human immunoglobulin kappa light chain was used as a calibration standard for ADA quantitation. The final LC-MS method contains 17 multiple reaction monitoring (MRM) transitions and an optimized 15-min LC method. The results suggested that IgG1 was the most abundant isotype in ADA-positive samples. IgG2 and IgG4 were identified at lower levels, whereas IgG3 and IgA levels were only observed at very minor levels. In addition, levels of total ADA measured by the LC-MS assay were comparable to results obtained using a traditional ligand binding assay (LBA). The LC-MS ADA assay enabled rapid immunogenicity assessment with additional isotype information that LBAs cannot provide.

Humoral immunity factors in cynomolgus macaques (Macaca fascicularis) serum: immunoglobulins and total light chains in nursing dams

This study was aimed at the identification of variations in humoral immunity parameters during the lactation period in macaque females, a recognized model in reproductive physiology and pathology. The importance of such evaluation is evidenced in particular by the central role played by the maternally transferred immunity to the progeny. The trends of serum immunoglobulins and light chains were characterized by immunonephelometry during the 6-months of lactation. The levels attained by nursing females were evaluated against a control group. The main modifications induced by lactation were in the IgM class, whose levels remained constantly lower than in the control group; the other Igs, even if showing different trends, returned to levels comparable to the control group by the end of the sixth month. Light chains quantification evidenced a significant decrease in Kappa levels; Lambda chains showed a similar trend. The variation of the Kappa/Lambda ratio was therefore minimal.

Generation of monoclonal antibodies to Macaca mulatta (rhesus) IgA

One IgG1 and five IgM murine monoclonal antibodies (mAb) specific for rhesus (Rh) IgA were generated. These mAbs bound to Rh IgA but not IgG or IgM when tested by enzyme-linked immunosorbent assay. Immunoblotting revealed that the mAbs reacted with the alpha heavy chain of Rh but not human IgA. The IgG1 anti-Rh IgA mAb detected IgA-producing cells in sections of monkey gut examined by immunofluorescent staining. These mAbs should be useful for characterizing IgA responses in the Rh monkey.

Site of catabolism of autologous and heterologous IgA in non-human primates

Because of similarities between the human and monkey immune systems, we considered the monkey a suitable model for studies on the catabolism of various molecular forms of IgA, for which little information is available. The residualizing label dilactitol-[125I]tyramine was coupled to monkey (Macaca fuscata) IgA and IgG, as well as to human monomeric and polymeric myeloma IgA1 and IgA2 proteins. When labelled proteins were injected intravenously into monkeys, the non-metabolizable radioiodinated tracer accumulated at the cellular site of protein degradation, allowing identification of the catabolic sites. To determine the uptake of injected proteins by various tissues, monkeys were sacrificed 6-7 days after injection of labelled proteins, when blood-associated radioactivity was less than or equal to 10% of the injected dose, as measured by plasma clearance. When monkey or human monomeric IgA, as well as human polymeric IgA, irrespective of subclass, was administered to monkeys, the liver showed the greatest tissue uptake relative to total dose injected and to organ weight, and the highest acid soluble radioactivity (degraded protein). Although both hepatocytes and non-parenchymal liver cells were involved in IgA uptake, the hepatocytes were more active. Therefore, it appears that the liver is the major site of uptake and catabolism of IgA in monkeys and possibly in humans.

Effects of age, sex, and psychological disturbance on immunoglobulin levels in the squirrel monkey

The following research assessed the influence of developmental, hormonal, and psychological factors on immunoglobulin and complement protein levels in the squirrel monkey. A cross-sectional life span study established that the developmental pattern of immunoglobulins and complement proteins was similar to that observed in humans. IgG and IgM levels rose progressively with age, while the complement system was mature at birth. In contrast to humans, this species showed a significant sex difference in IgG levels, with higher levels in males during both infancy and adulthood. Males also showed a greater antibody response to viral challenge than did females, and evaluation of gonadectomized subjects suggested that the sex difference in antibody production was testosterone-dependent. The effect of acute and sustained psychological disturbance on IgG levels was also evaluated in infant monkeys. Repeated, brief separations from the mother did not alter IgG levels, but IgG levels were suppressed after a 7-day removal from the mother. Therefore, despite the general view that immunoglobulin levels are relatively stable, these studies have established that immunoglobulin levels can be strongly influenced by hormonal and experiential factors in the squirrel monkey.

Comparison of antigenicity of serum immunoglobulin G among human, cynomolgus monkey, African green monkey and squirrel monkey

Antigenicity of IgG was compared among human, the cynomolgus monkey, the African green monkey and the squirrel monkey by the quantitative precipitation test using purified IgG of and rabbit anti-IgG serum to each species. Clear cross-antigenicity was observed between the cynomolgus monkey and the African green monkey and less clear cross-antigenicity between human and the cynomolgus monkey or the African green monkey. The cross-antigenicity observed between the squirrel monkey and the other three species examined was evidently weak.

Elimination of toxicity from diets containing alfalfa seeds

Cynomolgus macaques were fed autoclaved alfalfa seeds for up to 1 yr. There were no humoral signs of a syndrome resembling systemic lupus erythematosus. The data are in contrast to those previously reported in monkeys fed raw alfalfa seeds, in which a systemic lupus erythematosus-like syndrome was induced in a shorter interval. The autoclaved seeds retained antihypercholesterolaemic effects.

Binding of immunoglobulins to protein A and immunoglobulin levels in mammalian sera

The use of protein A from S. aureus (SpA) as an anti-IgG reagent in immunological techniques has extended in recent years, together with knowledge about its interaction with immunoglobulins of different species. Current data with respect to the binding of protein A to immunoglobulins and to the levels of immunoglobulins in the sera of some mammalian species are reviewed.

Diet-induced systemic lupus erythematosus (SLE) in primates

Ten adult, female cynomolgus macaques were randomly assigned to two equal groups: (1) semipurified diet (SPD); and (2) SPD with 45% ground alfalfa seed (AS). Both groups were studied at monthly intervals after 5 mo on their respective diets. Control animals had a mean hematocrit (Hct) of 43 +/- 2%, negative antiglobulin (AG), antinuclear antibody (ANA) and LE cell tests. Mean values for C3 and C4 were 309 +/- 47 mg/dl and 35 +/- 7 mg/dl, respectively. Mean serum binding to radiolabeled double stranded deoxyribonucleic acid (dsDNA) was 1.9 +/- 0.2%. Three of five animals fed AS developed signs of an SLE-like illness characterized by AG-positive anemia (lowest Hct 30%), positive ANA (highest titer greater than 1:15, 360; rim pattern) and elevated anti-dsDNA binding (highest 96%) with variable degrees of hypocomplementemia. One animal had granular deposition of immunoglobulin and complement at the dermal-epidermal junction of clinically normal skin the presence of immune complex-induced glomerulonephritis.

Immunoglobulin epitopes in primates

Non-human primate sera were investigated for the presence of various human immunoglobulin epitopes including allotypes of kappa-, gamma 1-, gamma 2-, gamma 3- and alpha 2-chains, isotypes of kappa-, gamma 1-, gamma 2-, gamma 3-, gamma 4-, alpha 1-, alpha 2- and mu-chains and iso-allotypes. The non-human primate sera comprised representatives of several species of apes, Old World Monkeys, New World monkeys and prosimians. It is concluded that non-human primate immunoglobulins have many structural similarities with those of human IgM, IgA and IgG. The extent of these similarities parallels the taxonomic classification.

Radioimmunoassay of class-specific antibodies to Streptococcus mutans in monkey serum and saliva

A radioimmunoassay (RIA) has been developed to measure class-specific antibodies to Steptococcus mutans in the serum and saliva of monkeys (Macaca fascicularis). Anti-human immunoglobulin antibodies purified by affinity chromatography on immobilised monkey immunoglobulins and labelled with 125I were employed. Formolised cells of S. mutans and an extract of culture supernatant adsorbed to polystyrene wells were used as solid-phase antigens. The coefficients of variation for IgG, IgA and IgM assays were less than or equal to 10% for both antigen systems. Two monkeys were immunised with formolised cells of S. mutans by subcutaneous injection and subsequent instillation of bacterial cells into their right parotid ducts. IgG, IgA and IgM antibody responses to S. mutans in samples of serum and saliva were quantitated by RIA. Immobilisation of purified components of S. mutans on polystyrene wells enabled the measurement of antibody response to a number of antigens to be made. The RIA is a sensitive, reproducible and quantitative method of measuring serum and salivary antibody responses in monkeys.

Production of antibodies to human immunoglobulins in a gibbon

Immunization of a chimpanzee, a gibbon, a baboon and a rhesus monkey with human globulins gave different results. While chimpanzees did not produce any anti-human antibodies, baboon and rhesus monkey responded by producing anti-human IgG antibodies that did not show subclass or allotype specificity. In the gibbon antiserum, on the other hand, six different antibodies were demonstrated with a specificity against one or more of the four human IgG subclasses, including one allotype. Comparative investigations of non-human primate species sera showed that one of the specificities detected by these antibodies, i.e., the allotype G1m(f), was restricted to man; the other five antibodies reacted with man and with two or more genera of apes. Lower primates did not share any of these antigenic determinants. The extent of immunological distance is parallel to the taxonomic classification. The gibbon shows that there are more similarities between man and chimpanzee or pygmy chimpanzee than between man and gorilla or orangutan.

Passive immunisation with serum and immunoglobulins against dental caries in rhesus monkeys

Active immunisation with Streptococcus mutans induced protection against dental caries in rhesus monkeys, and this was associated with serum antibodies. Passive transfer of immune serum with IgG, IgM, and IgA antibodies to Strep. mutans failed to induce protection against dental caries. However, when separated IgG, IgM, and IgA sera were given, IgG induced significant protection but IgA or IgM antibodies to Strep. mutans did not. IgA and IgM may compete or interfere with the protective effect of IgG antibodies, and the ratio of IgG/IgA and IgG/IgM antibodies might be an important factor in immunisation against dental caries.

Passive immunization with antisera to Streptococcus mutans in the prevention of caries in rhesus monkeys

1) The immunological mechanism of protection against dental caries has been investigated by passive immunization with antisera to S. mutans in the rhesus monkey. 2) Passive immunization with separated IgG, IgM and IgA from sera of immunized monkeys supports the concept that IgG, unlike IgA or IgM antibodies are protective. 3) The role of cell-mediated immunity has been explored by the use of transfer factor. This showed that protection against dental caries can be elicited by passive transfer of whole immune serum and cellular immunity, but not by cellular immunity or immune serum alone. 4) The results of active and passive immunization suggests that immuno-regulation of T and B cell interactions plays an important part in the effector mechanism of opsonization, phagocytosis and killing of S. mutans.

Immunoglobulins A, G, and M in serum and in some secretions of monkeys (Macaca fascicularis syn. irus)

The purpose of this investigation was to study the distribution and levels of the following immunoglobulins, IgA, IgG, and IgM ,in sera and in some secretions of monkeys (M. fascicularis). IgG, IgA, and IgM were isolated from monkey serum and secretory IgA was separated from monkey milk by combined gel filtration and ion-exchange chromatography. These pure preparations served as standards to quantitate immunoglobulins in sera and secretions by single radial immunodiffusion. Antisera were raised in the rabbit against the pure immunoglobulins and also against the whole secretions to identify the immunoglobulins in immunoelectrophoresis. In common with humans, the major immunoglobulin in serum and amniotic fluid is IgG and the IgG/IgA ratio is greater than unity. In secretions IgA is the dominant immunoglobulin and the IgG/IgA ratio is less than 1. In general, the levels of immunoglobulins in the sera and secretions of monkeys paralleled the levels found in humans. No age-related increase in immunoglobulin levels was detected in the sera of monkeys.

Simian model for the evaluation of immunity to influenza

Rhesus monkeys (Macaca mulatta) exposed to small-particle aerosols of the Aichi strain of type A2 influenza virus responded by shedding virus from the nasopharynx for 7 to 9 days and by seroconversion (hemagglutination inhibition) 8 or 9 days after exposure. After rechallenge with the homologous virus, no replication of the organism was observed, and a serological anamnestic reaction occurred. The data indicate that the rhesus monkey is a useful primate model for evaluating induced immunity to influenza virus infection.

Local antibody response to experimental poliovirus infection in the central nervous system of rhesus monkeys

By employing the techniques of immunofluorescence and radioimmunodiffusion using (32)P-labeled poliovirus as the antigen, the immunoglobulin response to poliovirus in serum, nasopharynx, spinal fluid, and in different segments of the central nervous system (CNS) was studied after intramuscular, oral, intranasal, and intrathalamic administration of inactivated (Salk), live attenuated (Sabin), or live virulent (Mahoney) type I poliovirus. Spinal fluid gammaG antibody was detected after immunization with Sabin or Mahoney virus and intramuscular administration of Salk vaccine. The response in the CNS was characterized by the appearance of gammaG antibody after oral or intrathalamic administration of Mahoney virus and rarely after intrathalamic inoculation of Sabin vaccine. The antibody activity in CNS was limited to the areas of poliovirus replication. Intrathalamic immunization with Mahoney virus resulted in local gammaG antibody production in the CNS in the absence of any detectable response in serum. Discrete foci of gammaG-containing cells were observed in those areas of CNS which contained poliovirus antibody. No immunoglobulin-containing cells or poliovirus antibody was seen in the CNS of monkeys immunized with intramuscularly or orally administered Sabin or Salk vaccine and in sham-immunized control monkeys. It is suggested that the CNS, when stimulated locally with a potent replicating viral antigen, may manifest a specific local antibody response, which is independent of the response in serum.