Serial injection of muramyldipeptides and liposomes enhances the anti-infective activity of muramyldipeptides.

Serial injection of muramyldipeptides and liposomes enhances the anti-infective activity of muramyldipeptides

Four hundred and seventy-five strains, which included 394 type cultures of Streptomyces and representatives of 14 other actinomycete genera, were studied. Overall similarities of these strains for 139 unit characters were determined by the SSM and SJ coefficients and clustering by the UPGMA algorithm. Test error and overlap between the phena defined were within acceptable limits. Cluster-groups were defined by the SSM coefficient at the 70.1% similarity (S) level and by the SJ coefficient at the 50% S-level. Clusters were distinguished at the 77.5% SSM and 63% SJ S-levels. Groupings obtained with the two coefficients were generally similar, but there were some changes in the definition and membership of cluster-groups and clusters. The phenetic data obtained, together with those from previous diverse studies, indicated that the genera Actinopycnidium, Actinosporangium, Chainia, Elytrosporangium, Kitasatoa and Microellobosporia should be reduced to synonyms of Streptomyces, while Intrasporangium, Nocardioides and Streptoverticillium remained as distinct genera in the family Streptomycetaceae. Nocardiopsis dassonvillei also showed strong phenetic affinity to Streptomyces, despite its chemotaxonomic differences. Actinomadura sensu stricto was phenetically distinguishable from Streptomyces and 'Nocardia' mediterranea was recognized as a taxon distinct from both these genera and from Nocardia sensu stricto. Most of the Streptomyces type cultures fell into one large cluster-group. At the 77.5% SSM S-level, they were recovered in 19 major and 40 minor clusters, with 18 strains recovered as single member clusters. The status of the latter as species was therefore confirmed. Most of the minor clusters, consisting of two to five strains, can also be regarded as species. The major clusters varied in size (from 6 to 71 strains) and in there homogeneity. Therefore, it is suggested that they be regarded as species-groups until further information is available. The results provide a basis for the reduction of the large number of Streptomyces species which have been described. They also demonstrate that the previous use of a limited number of subjectively chosen characters to define species-groups or species has resulted in artificial classifications.

Numerical Classification of Streptomyces and Related Genera

Pattern recognition receptors: doubling up for the innate immune response.

Minimal structural requirements for adjuvant activity of bacterial peptidoglycan derivatives.

The problem with pure recombinant or synthetic antigens used in modern day vaccines is that they are generally far less immunogenic than older style live or killed whole organism vaccines. This has created a major need for improved and more powerful adjuvants for use in these vaccines. With few exceptions, alum remains the sole adjuvant approved for human use in the majority of countries worldwide. Although alum is able to induce a good antibody (Th2) response, it has little capacity to stimulate cellular (Th1) immune responses which are so important for protection against many pathogens. In addition, alum has the potential to cause severe local and systemic side-effects including sterile abscesses, eosinophilia and myofascitis, although fortunately most of the more serious side-effects are relatively rare. There is also community concern regarding the possible role of aluminium in neurodegenerative diseases such as Alzheimer's disease. Consequently, there is a major unmet need for safer and more effective adjuvants suitable for human use. In particular, there is demand for safe and non-toxic adjuvants able to stimulate cellular (Th1) immunity. Other needs in light of new vaccine technologies are adjuvants suitable for use with mucosally-delivered vaccines, DNA vaccines, cancer and autoimmunity vaccines. Each of these areas are highly specialized with their own unique needs in respect of suitable adjuvant technology. This paper reviews the state of the art in the adjuvant field, explores future directions of adjuvant development and finally examines some of the impediments and barriers to development and registration of new human adjuvants.

Vaccine adjuvants: current state and future trends.

In the following pages we intend to update and to expand a previous review 'The Mycobacterial cell wall' published in 19711 . Many new facts on the chemical structure have come to light since then and the last few years have witnessed a rapid expansion of our knowledge of the interesting biological properties of compounds derived from the cell walls of Mycobacteria and related organisms especially the Nocardiae. We shall first discuss the chemistry, then the biological properties involved.

Cell walls of Mycobacteria and related organisms; chemistry and immunostimulant properties.

Adjuvant activity of monomeric bacterial cell wall peptidoglycans.

Trypsin- and chymotrypsin-treated delipidated cell walls of Mycobacterium smegmatis were digested overnight with lysozyme. The water-soluble products thus obtained were filtered on a column of Sephadex G-50; the first peak, excluded from the column, has immunological adjuvant activity. The material of the excluded peak is obtained after lyophilization as a snow-white, fluffy material, soluble in water and insoluble in organic solvents. It behaves as a slightly polydisperse macromolecule in an ultracentrifuge, with an approximate molecular weight of 20,000. All the constituents of this material are typical bacterial cell-wall constituents; thus, the water-soluble adjuvant is considered to be an "oligomer" of the cell wall. When added to Freund's incomplete adjuvant with an antigen (e.g., ovalbumin) and injected into hind-foot pads of guinea pigs, this water-soluble adjuvant increases the amount of precipitating antibodies and induces hypersensitivity to ovalbumin and the biosynthesis of gamma(2)-type precipitating antibodies. The water-soluble material has a stronger adjuvant activity than equal amounts of whole bacteria, cell walls, or wax D, and seems to be the first well-defined, water-soluble, adjuvant-active fraction isolated from Mycobacteria.

https://www.pnas.org/content/pnas/69/4/851.full.pdf

Isolation and properties of a macromolecular, water-soluble, immuno-adjuvant fraction from the cell wall of Mycobacterium smegmatis.

Delipidated lysozyme digests of Nocardia opaca, N. corallina, and N. rubra have been fractionated by Sephadex filtration. The mitogenic and adjuvant activities of the fractions thus obtained have been investigated. All fractions are mitogenic except the last fraction of N.rubra, but the N. opaca products induce a stronger stimulation of mouse spleen lymphocytes than the corresponding fractions of the two other species. The activity of the first Sephadex fractions of each strain has been compared to other mitogens (concanavalin A, lipopolysaccharide). All fractions are adjuvant, although one of them, the last Sephadex fraction of N. rubra, does not contain peptidoglycan; its activity must thus be attributed to another kind of molecule. Fractionation of the first Sephadex fraction of N. opaca by centrifugation in glacial acetic acid led to a separation of adjuvant and mitogenic activities.

Rita Ciorbaru

Papers

Minimal structural requirements for adjuvant activity of bacterial peptidoglycan derivatives.

Cell walls of Mycobacteria and related organisms; chemistry and immunostimulant properties.

Adjuvant activity of monomeric bacterial cell wall peptidoglycans.

Isolation and properties of a macromolecular, water-soluble, immuno-adjuvant fraction from the cell wall of Mycobacterium smegmatis.

Isolation of mitogenic and adjuvant active fractions from various species of Nocardiae.