## 4 Plant Tissue and Organ Cultures in Bioreactors
### Temporary Immersion System
Table 2 presents selected examples of proteins obtained from transgenic plants that were cultured in bioreactors, including recombinant human butyrylcholinesteraseterase (BChE), human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4 lg), human granulocyte-macrophage colony-stimulating factor (hGM-CSF), mouse granulo-cyte-macrophage colony stimulating factor (mGM-CSF), recombinant human serum albumin (rHSA) from _Oryza sativa_; isoform 1 of the human growth hormone (hGH1) from _Brassica oleracea_; protein A (OspA) from Borrelia burgdorferi, human monoclonal anti-body M12--a vaccine antigen--fragment C of tetanus toxin (TetC)/green fluorescent protein (GFP+), green fluorescent protein-hydrophobic fusion (GFP-HFBI) from _N. tabacum_; recombinant protein containing a fusion of rabies glycoprotein and ricin toxin B chain (rgp-trkB) from _Solanum lycopersicum_; factor H (FH) and FH-related proteins (FHRs) from _Physcomitella patens_; and human tissue-plasminogen activator (t-PA) protein from _Cucumis melo_. The details about the vectors or genetic construct elements, as well as the culture's conditions in bioreactors, are also included. The presented examples showed that plant systems are good models for the production of recombinant proteins. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Name of the Species/Family** & **Type of Culture** & **Vector/Genetic** & **Recombinant Protein** & **Type of Bioreactor** & **Medium/ Elicitors Used** & **Effect/Vield** & **Ref.** \\ \hline \multirow{3}{*}{_Oryza sativa_ L\_/ _Powace_} & & metabolically-regulated promoter, & recombinant human & & -half-strength & -the method significantly improved the maximum & \\  & & regulated promoter, & butylycholinesterase & 5-L stirred-tank & sucrose of the & accumulation level, purity, & [168] \\  & & culture & rice alpha-amylase 3D & (BChE), & & & culture medium & recombinant protein \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Overproduction of recombinant proteins in transgenic cultures grown in bioreactors. A common protein produced by transgenic plants is butyrylcholinesterasesterase (BuChE), an enzyme in the serine hydrolase family that catalyzes the hydrolysis reaction of both choline and non-choline esters, including acetylcholine. Acetylcholine is an important neurotransmitter released by cholinergic neurons. Moreover, BuChE enhances the activity of proteases, including trypsin. In the human brain, its expression takes place in substantial populations of neurons and might be related to their growth during the development of the nervous system. Their enzymatic properties are altered in Alzheimer's disease [187]. Besides somatic growth, growth hormone also has an effect on brain function. The receptors are present in areas underlying cognitive function. Growth hormone treatment can stimulate growth and improve cognition in deficient children [188; 189]. There are also a group of proteins related to immune system action that could be produced by plant systems. For example, T lymphocyte antigen-4 (CTLA-4) plays an important role in the initial phase of the immune response via inhibition of T-cell effector function. _Ctl4_ knockout mice exhibit lymphocyte infiltration into various organs and early lethality. Therefore, human monoclonal antibodies that target CTLA-4 increase T cell function as well as antitumor responses in cancer patients [190; 191]. Granulocyte-macrophage colony-stimulating factor (GM-CSF) also plays an important immune modulatory role by enhancing the function of circulating neutrophils, monocytes, and lymphocytes during host defense as well as crucial hematopoietic growth factor. Neutrophils are also activated by a protein named protein A (OspA) expressed by _Borrelia burgdorferi_[192; 193]. The crucial part of the human immune system is the complement system, which is negatively regulated by _inter alia_ factor H (FH). FH was produced for the first time by _Physcomittella patens_ in a moss bioreactor. Improper FH activity results in severe kidney and eye diseases [185].