Immune response cationized molecules

Figure 273 Cationized BSA even can increase the specific antibody response to large proteins coupled to it. This graph shows a comparison of the relative antibody response in mice to injections of ovalbumin, either in an unconjugated form or conjugated to native or cationized BSA. The quantity injected was standardized according to the amount of ovalbumin present. The highly basic cBSA molecule modulates the immune response to enhance the production of antibodies toward even proteins conjugated with it.

Since 2002, on-line nanoscale LC-ESI-MS/MS was used for the analysis of the peptidome of. Drosophila samples. This combination greatly improves the sensitivity of detection. Starting from only 50 larval Drosophila CNS, 28 peptides were isolated and sequenced in an on-line quadrupole time-of-flight mass spectrometer [27]. Later, two-dimensional capillary LC-ESI-MS/MS has enhanced the coverage of this peptidomics analysis with the identification of twenty additional peptides [31]. The CNS extract has been first fractionated onto a strong cation-exchange column then onto a reversed-phase column before ESI-MS/MS analysis. Recently this approach has been applied to Drosophila larvae hemolymph to identify new peptides induced by a septic injury [22]. Most of the identified molecules correspond to truncated forms or propeptides of known AMPs and DIMs [15,20,21], but two previously unknown peptide precursors, potentially involved in the innate immune response, have been also detected by this way. 

Cationic peptides have also been used as DNA carriers. For example, gramicidin S and tyrocidine are cationic peptides that will bind to plasmid DNA. When combined with DOPE, the peptide/DNA complex has been shown to transfect cells in vitro. The efficiency of the peptide compared to liposome/ DNA complexes varies by cell type, but the toxicity is equally low (65). Other types of cationic peptides have also been utilized for gene transfer, and they are most effective in combination with molecules that exhibit pH-dependent membrane perturbation effects (30,66). Presumably these helper components promote endocytic escape after cellular uptake. Cationic peptide-type carriers are not in wide usage at this time, particularly in vivo. It will be interesting to see if these peptides induce any immune response when administered to animals. 

Transfer of calcium cations (Ca2 + ) across membranes and against a thermodynamic gradient is important to biological processes, such as muscle contraction, release of neurotransmitters or biological signal transduction and immune response. The active transport can be artificially driven (switched) by photoinduced electron transfer processes (Section 6.4.4) between a photoactivatable molecule and a hydroquinone Ca2 + chelator (405) (Scheme 6.194).1210 In this example, oxidation of hydroquinone generates a quinone to release Ca2+ to the aqueous phase inside the bilayer of a liposome, followed by reduction of the quinone back to hydroquinone to complete the redox loop, which results in cyclic transport of Ca2 +. The electron donor/acceptor moiety is a carotenoid porphyrin naphthoquinone molecular triad (see Special Topic 6.26). 

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