Archives June 2020

ADVANTAGES AND DISADVANTAGES OF THE DIFFERENT TYPES OF ELISA

With this entry we conclude the series of posts where we have delved into the peculiarities of the different types of ELISA.

After knowing the rationale and procedure on which each of them is based and seeing the main characteristics that differentiate them , today we will focus on analyzing the advantages and disadvantages of the different types of ELISA .

ADVANTAGES AND DISADVANTAGES OF THE DIFFERENT TYPES OF ELISA

In order to make this entry as visual and practical as possible, we will summarize and group the main advantages and disadvantages of the different types of ELISA in the following table:

TYPES OF ELISAADVANTAGEDISADVANTAGES
ELISA direct1.- The protocol is simple and fast.2.- There is no possibility of cross reactivity with the secondary antibody.3.- Less probability of error due to the use of fewer reagents and steps in the procedure.1.- It can give more background noise, since other proteins present in the sample (in addition to the antigen of interest) can adhere to the plate.2.- There is no signal amplification since secondary antibodies are not used, which reduces the sensitivity of the assay.3.- The primary antibody must be labeled, which reduces the flexibility of the assay, and can be used to alter its immunoreactivity.
Indirect ELISA1.- High sensitivity, since the use of secondary antibodies makes it possible to amplify the signal.2.- High flexibility due to the fact that the same secondary antibody can be used with different primary antibodies, which also translates into an economic benefit.3.- The primary antibody maintains its immunoreactivity intact by not being conjugated.1.- Protocol more complex than the direct ELISA, which includes additional incubation steps with the secondary antibody.2.- The use of secondary antibodies can lead to cross reactivity.
ELISA sandwich1.- High flexibility, since detection can be done both by direct and indirect procedure.2.- High sensitivity and specificity, due to the use of two antibodies against the same antigen.1.- The antigen must be large enough to allow two antibodies to bind simultaneously.2.- It is not always easy or possible to have pairs of antibodies that work well in this type of assay.
Competitive ELISA1.- High flexibility: it can be based on a direct, indirect or sandwich procedure.2.- High sensitivity, robustness and consistency.3.- It allows the detection of small size antigens and in low concentrations.4.- It does not require the previous processing of the samples to be analyzed.1.- The protocol is relatively complex.2.- Requires the use of inhibition antigen.

As a conclusion after analyzing the advantages and disadvantages of the different types of ELISA, we can determine the ideal use of each of them :

  • Direct ELISA : it is the technique of choice to analyze the immune response to a certain antigen, for example, in the production of antibodies or in diagnostic procedures.
  • Indirect ELISA : test of choice to determine the total concentration of antibodies in a certain sample.
  • Sandwich ELISA : technique of choice when it comes to analyzing complex samples, without the need to purify the antigen previously.
  • Competitive ELISA : ideal technique to detect antigens of small size or that are present in very low concentrations in the sample.

MONOCLONAL ANTIBODIES NOMENCLATURE

For all medicines and therapeutic agents , the WHO (World Health Organization) assigns a generic name known as INN ( International Non- proprietary Name ) in order to facilitate the identification of the active pharmaceutical ingredients that comprise it.

This INN is also applicable in the case of monoclonal antibodies , which are assigned a generic name based on a specific schematic structure. The International Nonproprietary Name (INN) for each monoclonal antibody is composed of a prefix, two intermediate particles that serve the type of target to which the monoclonal antibody is directed and the species of origin thereof, respectively, and a common suffix for all of them.

Want to know what the names of the antibodies mean? In this entry we analyze the scheme and the specific structure that is followed in the monoclonal antibody nomenclature.

MONOCLONAL ANTIBODIES NOMENCLATURE

As we said, the name or INN of each monoclonal antibody is assigned based on a scheme that includes 4 aspects:

  • Random prefix
  • Target type
  • Origin species
  • Common suffix

Let’s take a closer look at each of them:

1.- RANDOM PREFIX

This part of the monoclonal antibody name or INN does not meet any specific criteria. Its “function” is to distinguish one monoclonal antibody from another (since the name of two antibodies directed at the same target and originating from the same species will only be distinguished by the prefix), so it must be unique, and it is free choice by the manufacturer of the same.

2.- TARGET TYPE

After the random prefix, a particle representing the type of target to which the monoclonal antibody is directed is added. This particle generally consists of a consonant to which a vowel is added only in the case where the particle representing the origin of the antibody begins with a consonant.

3.- ORIGIN SPECIES

Third, the particle corresponding to the origin of the monoclonal antibody is added, and it can be of animal, chimeric, humanized or totally human origin.

4.- SUFFIX

The names of all monoclonal antibodies will always end with the common suffix -mab , indicating that it is an immunoglobulin or a fragment of it, provided that it includes at least one variable domain.

Although the monoclonal antibody nomenclature may seem confusing or complicated at first glance, it is actually very precise and easy to understand based on these criteria that we have just discussed, and which we summarize in the following table:

PrefixTarget typeOrigin speciesSuffix
Random-b (a) – bacterial-am (i) – serum amyloid protein (SAP) / amyloidosis (pre-substem)-c (i) – cardiovascular-f (u) – fungal-gr (o) – skeletal muscle mass related growth factors and receptors (pre-substem)-k (i) – interleukin-l (i) – immunomodulating-n (e) – neural-s (o) – bone-tox (a) – toxin-t (u) – tumor-v (i) – virala- rat-axo- rat-mouse (pre-substem)-e- hamster-i- primate-o- mouse-u- human-vet- veterinary use (pre-substem)-xi- chimeric-xizu- chimeric-humanized-zu- humanized-mab

To finish, we leave you some examples to understand the information provided by the monoclonal antibody nomenclature:

  • BASILIXIMAB
    • Basi- (prefix)
    • -li- (immunomodulator)
    • -xi- (of chimeric origin)
    • -mab (monoclonal antibody)
  • INFLIXIMAB
    • Inf- (prefix)
    • -li- (immunomodulator)
    • -xi- (of chimeric origin)
    • -mab (monoclonal antibody)
  • PALIVIZUMAB
    • Pali- (prefix)
    • -vi- (against a viral antigen)
    • -zu- (humanized)
    • -mab (monoclonal antibody)
  • TRASTUZUMAB
    • Tras- (prefix)
    • -tu- (against tumor antigens)
    • -zu- (humanized)
    • -mab (monoclonal antibody)